Weather - May 26

By: beell , 1:27 PM GMT on May 26, 2014

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430. WunderAlertBot (Admin)
10:46 AM GMT on July 01, 2014
beell has created a new entry.
429. Barefootontherocks
3:15 AM GMT on July 01, 2014
LOL. That was funny.
'Nite again.
Quoting beell:


Manuel says the difference is usually less than 5 minutes, bf...
'Nite, All.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
428. beell
3:11 AM GMT on July 01, 2014
Quoting 427. Barefootontherocks:

Jinx, 2:32 am!
I hope Manuel (hello back) can tell a slip from a bra strap, bl.

Quiet weather would be lovely. 'Nite!




Manuel says the difference is usually less than 5 minutes, bf...
'Nite, All.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
427. Barefootontherocks
2:59 AM GMT on July 01, 2014
Jinx, 2:32 am!
I hope Manuel (hello back) can tell a slip from a bra strap, bl.

Quiet weather would be lovely. 'Nite!

Member Since: April 29, 2006 Posts: 151 Comments: 18530
425. beell
2:35 AM GMT on July 01, 2014
bf, my operating Manuel (says hello) clearly states that rolling to a new blog is to be on the first of the month unless we are in an active weather period. I am ready for both however-inactive and new.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
424. beell
2:32 AM GMT on July 01, 2014
Oh! Ya'll are/were here!

Yeah, Rand. She got mine off mugshots.com. And you?

I have pics of aqua marrying some other guy than me! Imagine that....

I've seen those pics. It looked like a beautiful ceremony-except for one guy...
Good to hear from you V. You "sound" good. Stop by anytime, sir.

Stop that, bf. Your slip is showin'!
Member Since: September 11, 2007 Posts: 142 Comments: 16478
423. Barefootontherocks
2:32 AM GMT on July 01, 2014
Hi bl,
Only two and a half hours left if you want to have a blog for June. (Yes I am a backseat driver.)
:)


LPL, aqua.
I'd like to see those.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
421. aquak9
11:20 PM GMT on June 30, 2014
I have pics of both Beell AND Randrewl.

Bidding starts at $100.
Member Since: August 13, 2005 Posts: 164 Comments: 25825
420. Barefootontherocks
11:08 PM GMT on June 30, 2014
Hey, baby. Where you been all my life? LOL Good to see you!

(I will now quietly slink off. I hope.)
Member Since: April 29, 2006 Posts: 151 Comments: 18530
418. Barefootontherocks
10:47 PM GMT on June 30, 2014
Looks like the bottom "bookend" is breaking off, leaving a (hopefully) weakened tale going jus' direction.

Enjoy your eve, bl.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
417. Barefootontherocks
10:25 PM GMT on June 30, 2014
Hey. Stop that.
More to come...

MESOSCALE DISCUSSION 1221
NWS STORM PREDICTION CENTER NORMAN OK
0512 PM CDT MON JUN 30 2014

AREAS AFFECTED...NRN MO

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 302212Z - 302315Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...THUNDERSTORMS MAY INCREASE IN COVERAGE ALONG STALLING
OUTFLOW BOUNDARY...AND THEN SPREAD EWD/ESEWD ACROSS NRN MO. A WATCH
MAY BECOME NECESSARY BEFORE 23Z.

DISCUSSION...NEW THUNDERSTORM DEVELOPMENT IS OCCURRING NEAR THE NW
MO/SW IA BORDER...JUST E OF THE INTERSECTION OF THE OUTFLOW BOUNDARY
TRAILING FROM THE SW WI/NW IL MCS AND THE SYNOPTIC COLD FRONT.
STRONG BUOYANCY REMAINS ALONG AND S OF THE E-W ORIENTED OUTFLOW
BOUNDARY...AND THIS CORRIDOR IS ALONG THE SRN FRINGE OF THE STRONGER
MIDLEVEL WLYS. THE COMBINATION OF PEAK AFTERNOON TEMPERATURES TO
WEAKEN CONVECTIVE INHIBITION...AND A GLANCING INFLUENCE OF THE
SHORTWAVE TROUGH/SPEED MAX MOVING ESEWD OVER THE MID MO
VALLEY...WILL SUPPORT THE RISK FOR ADDITIONAL THUNDERSTORM
DEVELOPMENT THIS AFTERNOON. LOW-LEVEL SHEAR IS NOT EXPECTED TO
INCREASE...BUT DEEP-LAYER SHEAR WILL REMAIN SUFFICIENT FOR
SUPERCELLS ACROSS NRN MO...AND THE MOIST BOUNDARY LAYER WITH MLCAPE
AOA 4000 J/KG WILL BE AT LEAST MARGINALLY FAVORABLE FOR SOME TORNADO
RISK. OTHERWISE...LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE
WITH THE STRONGER STORMS...AND A NEW WATCH MAY BECOME NECESSARY
ACROSS NRN MO.


..THOMPSON/DIAL.. 06/30/2014
Member Since: April 29, 2006 Posts: 151 Comments: 18530
416. beell
10:14 PM GMT on June 30, 2014
I guess I should read my blog once in awhile!
Thanks.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
415. Barefootontherocks
10:07 PM GMT on June 30, 2014

MESOSCALE DISCUSSION 1220
NWS STORM PREDICTION CENTER NORMAN OK
0433 PM CDT MON JUN 30 2014

AREAS AFFECTED...PORTIONS OF NORTHERN ILLINOIS AND SOUTHERN
WISCONSIN

CONCERNING...SEVERE THUNDERSTORM WATCH 375...

VALID 302133Z - 302330Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 375
CONTINUES.

SUMMARY...WIDESPREAD DAMAGING WINDS ARE SPREADING ACROSS NORTHERN
ILLINOIS AND SOUTHERN WISCONSIN. EXPECT 60-75-MPH WINDS TO REACH
CHICAGO TO MILWAUKEE DURING THE 545 PM CDT TO 700 PM CDT TIME FRAME.
BRIEF TORNADOES MAY ALSO OCCUR.


DISCUSSION...THE ONGOING MATURE...DERECHO-PRODUCING MCS IS
EXHIBITING AROUND 50-55 KT OF FORWARD MOTION AND HAS LIKELY REACHED
PEAK INTENSITY
. WIDESPREAD DAMAGING WINDS HAVE BEEN REPORTED...WITH
A RECENT WIND GUST TO 78 MPH MEASURED IN SWRN WI. THE FAST SYSTEM
MOTION WILL ENHANCE INFLOW AMIDST AN EXTREMELY UNSTABLE AIR MASS TO
SUPPORT MCS MAINTENANCE AND WIDESPREAD DAMAGING WINDS ACROSS NRN IL
AND SRN WI INTO EARLY EVENING. LINEAR EXTRAPOLATION OF THE ONGOING
ACTIVITY TAKES THE SVR-WIND THREAT ACROSS THE CHICAGO AREA AND
MILWAUKEE...PRIMARILY BETWEEN 545 PM CDT AND 700 PM CDT. A FEW BRIEF
TORNADOES WILL ALSO BE POSSIBLE...PARTICULARLY WITH BOOKEND VORTICES
IN SRN WI AND ALONG FLANKS OF PROMINENT REAR-INFLOW JETS.


..COHEN.. 06/30/2014
Member Since: April 29, 2006 Posts: 151 Comments: 18530
414. beell
10:03 PM GMT on June 30, 2014

Static reflectivity loop-Davenport, IA (KDVN) ending at 21:57Z
Member Since: September 11, 2007 Posts: 142 Comments: 16478
413. beell
9:24 PM GMT on June 30, 2014
So, in the classic concept. the bookends feed into and help create the rear inflow notch.



The evolution of a bow echo. In the diagram at left, note the development of a rear-inflow jet at the center and "bookend" vortices on either end. In the Northern Hemisphere, the northern vortex tends to dominate later in the life cycle, creating a comma-shaped system. At right is a simulation of a squall line that includes several examples of bookend vortices. (Illustrations: COMET Program.)
ucar.edu/thunderstorm glossary

A rear inflow notch enters the backside of a storm in the middle levels of the troposphere. These inflow notches are particularly conducive to severe weather if they ingest high momentum and dry air into the storm. If the air is dry it will cool through evaporative cooling. This will increase the negative buoyancy of the air and it will accelerate toward the earth's surface. This negative buoyancy acceleration along with the air's initial high momentum can produce severe convective wind gusts at the leading edge of the storm or storm complex...
Haby's
Member Since: September 11, 2007 Posts: 142 Comments: 16478
412. Barefootontherocks
9:24 PM GMT on June 30, 2014
Quoting beell:
Classic rear inflow notch (1.) and book-end vortices (2.).

Dayum!

Thank you.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
411. Barefootontherocks
9:19 PM GMT on June 30, 2014
SPC issued a rare PDS Thunderstorm Watch corners of SE Wisc, NE IL and NW IN and a tiny bit of Michigan and south end of Lake Michigan. Tornado watches are in effect to the west of this thunderstorm watch.

Been some high wind reports and wind damage in IA. SPC referred to the MCS moving east from Iowa as "derecho-producing" in (edit) the watch. Link to the 3 pm Convective Outlook. From the sound of the outlook, MCD and watch discussions, it may pick up speed as it moves basically east and/or a tad ESE.


Click image for reports
Member Since: April 29, 2006 Posts: 151 Comments: 18530
410. beell
9:06 PM GMT on June 30, 2014
Classic rear inflow notch (1.) and book-end vortices (2.).

Member Since: September 11, 2007 Posts: 142 Comments: 16478
409. Barefootontherocks
8:12 PM GMT on June 30, 2014
Member Since: April 29, 2006 Posts: 151 Comments: 18530
408. Barefootontherocks
7:48 PM GMT on June 30, 2014
You know, the most interesting thing about this swirly-gig off Florida east coast, the pressure at the LLC is... what? 1012-1015 mb? Don't know yet the official from HH.


I'm hard-pressed to call 91L a depression, but it probably is. Next, I wonder what would happen with rapid height falls. Probable I am off-base. Uncharted territory for me.

Ps. I see the HH's just extrapolated a 1009.7mb surface pressure.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
407. Barefootontherocks
6:24 PM GMT on June 30, 2014
Hi Tf,
No accounting for personal taste I guess. ;)
Member Since: April 29, 2006 Posts: 151 Comments: 18530
406. Thunderfan
5:16 PM GMT on June 30, 2014
That sounds like some powerful stormage there BF. Funny, how this is way more powerful than 91L, but gathers so much less attention.
Member Since: April 14, 2012 Posts: 3 Comments: 790
405. Barefootontherocks
4:50 PM GMT on June 30, 2014
The 1130 Convective Outlook broadened the E side of moderate risk. 45% hatched for wind over a large area. Outlook excerpt...
...CNTRL PLNS TO MID/UPR MS VLY AND LWR MI TODAY/TNGT...
SETUP APPEARS FAVORABLE FOR SIGNIFICANT SVR WEATHER OVER THE LWR MO
AND MID MS VLYS TODAY INTO TNGT
. A BAND OF MODERATE TO STRONG WLY
DEEP SHEAR WILL OVERLIE A SIMILARLY-ORIENTED CORRIDOR OF SUBSTANTIAL
INSTABILITY IN THE PRESENCE OF AT LEAST MODEST LARGE-SCALE FORCING
FOR ASCENT. THIS SETUP COULD YIELD FAIRLY NUMEROUS SUPERCELLS THAT
WILL HAVE THE POTENTIAL FOR UPSCALE GROWTH INTO A DERECHO-PRODUCING
MCS.

Tornado probabilities. Click graphic for complete 1130 outlook.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
404. Barefootontherocks
4:39 PM GMT on June 30, 2014
And again...

MESOSCALE DISCUSSION 1213
NWS STORM PREDICTION CENTER NORMAN OK
1048 AM CDT MON JUN 30 2014

AREAS AFFECTED...NERN NEB INTO WEST CENTRAL AND CENTRAL IA

CONCERNING...TORNADO WATCH 373...

VALID 301548Z - 301715Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 373 CONTINUES.

SUMMARY...THROUGH AT LEAST 16-17Z...AN INCREASING THREAT FOR
DAMAGING WINDS EXISTS FROM FAR NERN NEBRASKA INTO WEST CENTRAL AND
CENTRAL IOWA ATTENDANT TO A FAST-MOVING BOWING LINE OF STORMS.

DISCUSSION...TRENDS IN MORNING RADAR IMAGERY SHOWED CLUSTERS OF
STORMS HAD GROWN UPSCALE INTO A FAST-MOVING BOWING LINE OF
STORMS...NOW LOCATED IN FAR NERN NEB. THIS BOW...MOVING EAST AT 50
KT
...PRODUCED AN OBSERVED WIND GUST TO 51 KT AT 1450Z AT NORFOLK,
NEBRASKA AND WILL BEGIN TO AFFECT ADJACENT WEST CENTRAL IA /SRN
PLYMOUTH COUNTY TO HARRISON COUNTY/ BY 16Z. AT THAT FAST FORWARD
SPEED...SIGNIFICANT WIND DAMAGE IS POSSIBLE. THE EWD TRACK IS
EXPECTED TO BE MAINTAINED...AT LEAST IN THE SHORT TERM /THROUGH
17-18Z/...WITH THIS BOW MOVING ALONG A STRONG INSTABILITY GRADIENT.

..PETERS.. 06/30/2014
Member Since: April 29, 2006 Posts: 151 Comments: 18530
403. beell
2:51 PM GMT on June 30, 2014
It are! SPC left the door open for potential earlier with MCD 1210. Followed up with:


click for discussion

Was not really looking for that. The outflow boundary(s) this stuff has left behind should become a factor later today.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
402. Thunderfan
2:10 PM GMT on June 30, 2014
This is quite impressive for such an early time of the day!

Member Since: April 14, 2012 Posts: 3 Comments: 790
401. beell
1:08 PM GMT on June 30, 2014

13Z Day 1 Probabilistic Tornado
(click image for all 13Z Outlook graphics


DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 AM CDT MON JUN 30 2014

VALID 301300Z - 011200Z

...THERE IS A MDT RISK OF SVR TSTMS CENTRAL...SRN AND ERN IA...NRN MO...CENTRAL/NRN IL...EXTREME SRN WI...

...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM TX PANHANDLE TO LOWER MI AND INDIANA...

...SUMMARY...
WIDESPREAD SEVERE THUNDERSTORMS CAPABLE OF LARGE HAIL...TORNADOES AND SWATHS OF WIND DAMAGE ARE EXPECTED ESPECIALLY THIS AFTERNOON INTO TONIGHT ACROSS MUCH OF THE CORN BELT AND MIDWEST. MORE WIDELY SCATTERED SEVERE STORMS WILL BE POSSIBLE ACROSS THE SOUTH-CENTRAL PLAINS.

...SYNOPSIS...
IN MID-UPPER LEVELS...CYCLONE NOW LOCATED OVER MB/ONT BORDER IS FCST TO FILL SLOWLY AS IT MOVES EWD ACROSS NORTHERNMOST REACHES OF ONT THROUGH REMAINDER PERIOD. SYNOPTIC-SCALE RIDGE IS FCST TO AMPLIFY AS IT MOVES ONSHORE PAC NW TODAY AND ACROSS INTERIOR NWRN STATES AND BC OVERNIGHT. IN BETWEEN THOSE SYNOPTIC FEATURES...SHORTWAVE TROUGH WAS APPARENT IN MOISTURE-CHANNEL IMAGERY OVER SRN/ERN MT. THIS PERTURBATION WILL AMPLIFY BUT RETAIN POSITIVE TILT AS IT MOVES ESEWD ACROSS NRN PLAINS TODAY...TO NEAR DLH-VTN LINE BY 00Z. SHORTWAVE TROUGH THEN SHOULD PIVOT NEWD AND DEAMPLIFY SOMEWHAT...REACHING ERN PORTIONS LS AND UPPER MI BY 12Z.

AREA OF LOW PRESSURE ANALYZED ON 11Z SFC CHART OVER WRN KS IS EXPECTED TO CONSOLIDATE INTO MORE COHERENT SFC LOW DURING DAYLIGHT HOURS AND MOVE ENEWD ALONG FRONTAL ZONE TOWARD NERN KS/NWRN MO...WHILE TRAILING BOUNDARY MOVES SWD OVER KS AS COLD FRONT. SAME FRONT ALSO WILL MOVE SEWD FROM NEB AND MN ACROSS MUCH OF IA THROUGH EVENING. DRYLINE WILL MIX EWD FROM MORNING POSITION OVER NERN NM AND ACROSS PORTIONS OK/TX PANHANDLES AND SWRN KS...WHERE IT WILL INTERSECT SWD-MOVING COLD FRONT.

...CENTRAL PLAINS TO MID/UPPER MS VALLEY AND LOWER MI...
REF SPC WWS 371-372 AND RELATED MESOSCALE DISCUSSIONS FOR LATEST NEAR-TERM INFO ON CONVECTION FROM WRN NEB TO CENTRAL IA.

EARLIER TSTMS OVER NRN/ERN IA HAVE PRODUCED PRONOUNCED OUTFLOW BOUNDARY THAT APPEARS TO FOCUS SVR POTENTIAL MORE TIGHTLY OVER IA...FOR MIDDAY THROUGH AFTN WITHIN MDT RISK AREA...AND WHICH ALSO INCREASES RISK OF SIGNIFICANT TORNADOES. VERY LARGE/DAMAGING HAIL STILL IS LIKELY FROM ANY SUSTAINED SUPERCELLS.

OUTFLOW BOUNDARY HAS BECOME ALIGNED CLOSE TO OR JUST RIGHTWARD OF MEAN FLOW...AND MAY BE REINFORCED LOCALLY BY CONVECTION NOW MOVING EWD OUT OF ERN NEB. ANY RELATIVELY DISCRETE SUPERCELL ALONG OR JUST N OF THAT BOUNDARY MAY HAVE SUSTAINED ACCESS TO VORTICITY-RICH AND DIABATICALLY DESTABILIZED AIR WITH SFC DEW POINTS LOW-MID 70S F...CONTRIBUTING TO MLCAPE 4000-5000 J/KG. SIMILARLY RICH MOISTURE/BUOYANCY WILL EXTEND SWD INTO PRECONVECTIVE WARM SECTOR...SUPPORTING RAPID GROWTH OF ANY FRONTAL CONVECTION. GREATEST JUXTAPOSITION OF STG BUOYANCY AND DEEP SHEAR THIS AFTN SHOULD BE OVER IA...ESPECIALLY WHEN CONSIDERING ENHANCEMENT TO LOW-LEVEL SHEAR/SRH RELATED TO OUTFLOW BOUNDARY.

FARTHER E...AIR MASS WILL TAKE LONGER TO RECOVER FROM MORNING CONVECTION/OUTFLOW OVER SRN WI/NRN IL/SWRN LOWER MI AND VICINITY. HOWEVER...SUSTAINED LOW-LEVEL WAA AND AREAS OF AFTN HEATING SHOULD ENABLE THAT PROCESS...WITH WAA CONTINUING IN PRECONVECTIVE REGIME AFTER 00Z. AS SUCH...DAMAGING-WIND THREAT WILL EXTEND INTO THESE REGIONS DURING EVENING INTO TONIGHT...EXCEPT FOR RELATIVE MIN OVER COLD NEAR-SFC MARINE LAYER OF LM. POTENTIAL EXISTS FOR NEB/IA CONVECTION TO EVOLVE UPSCALE AND PRODUCE SWATH OF SIGNIFICANT WIND DAMAGE -- PERHAPS WITH ENOUGH LATERAL/AREAL EXTENT TO CLASSIFY AS PROGRESSIVE DERECHO -- EWD AS FAR AS SWRN SHORES OF LM.

DAMAGING WIND AND OCNL LARGE HAIL ALSO ARE LIKELY FROM SQUALL LINE EXTENDING SWWD ALONG/AHEAD OF SFC COLD FRONT ACROSS REMAINDER IL AND MUCH OF CENTRAL/NRN MO.

...SOUTH-CENTRAL PLAINS...
CONVECTION IS EXPECTED TO DISCRETELY BACKBUILD SWWD INTO THIS REGION INVOF FRONT...AND ALSO WITHIN VERY WARM AND STRONGLY MIXING AIR NEAR DRYLINE. HEATING AND LIFT ALONG THOSE BOUNDARIES WILL OVERCOME EML-RELATED CAPPING AND TAKE ADVANTAGE OF VERY STEEP MIDLEVEL LAPSE RATES...AS WELL AS INCREASING BOUNDARY-LAYER MOISTURE WITH EWD EXTENT. THIS REGIME WILL RESIDE S OF SUBSTANTIAL MID-UPPER LEVEL LARGE-SCALE LIFT...WITH 25-35 KT EFFECTIVE SHEAR MAGNITUDES INDICATING DOMINANT MULTICELLULAR MODE AND ONLY TRANSIENT SUPERCELL POTENTIAL. DAMAGING GUSTS AND LARGE HAIL WILL BE MAIN THREATS...THOUGH A NON-SUPERCELL TORNADO OR TWO CANNOT BE RULED OUT WITH COLD-FRONTAL CONVECTION IN ITS EARLY STAGES WHEREVER INTENSE UPDRAFTS CAN STRETCH PRE-EXISTING VORTICITY ALONG FRONT. OVERALL SVR POTENTIAL SHOULD DIMINISH THROUGH LATE EVENING.

...SRN APPALACHIANS REGION...
SCATTERED TSTMS SHOULD DEVELOP THIS AFTN OVER THIS AREA AS BOUNDARY LAYER DESTABILIZES DIABATICALLY...NEAR AND AHEAD OF WEAK SHORTWAVE TROUGH THAT IS MOVING SLOWLY EWD OVER SRN APPALACHIANS ATTM. OUTFLOW/DIFFERENTIAL-HEATING BOUNDARIES FROM ONGOING CONVECTION ACROSS THIS REGION MAY FOCUS AFTN/SFC-BASED DEVELOPMENT ON MESOSCALE. FROM THERE...ADDITIONAL OUTFLOWS AND BOUNDARY MERGERS MAY SERVE THAT FUNCTION. WEAK DEEP SHEAR AND SMALL LAPSE RATES ABOVE BOUNDARY LAYER WILL LIMIT POTENTIAL FOR ORGANIZED SVR...BUT WELL-MIXED SUBCLOUD LAYERS AND WATER-LOADING IN PRECIP CORES SHOULD ENABLE RISK FOR DAMAGING GUSTS APCHG SVR LIMITS IN MOST INTENSE CORES.

..EDWARDS/JIRAK.. 06/30/2014
Member Since: September 11, 2007 Posts: 142 Comments: 16478
400. beell
11:32 AM GMT on June 30, 2014

Conus Water Vapor @ 1045Z


06/30 06Z NAM 500 mb Vort-Valid at 4PM CDT

Mid-level shortwave currently over Montana should time fairly well with peak heating this afternoon-although it may be lagging a bit and trending positive tilt. Both GFS and NAM are similar although the NAM seems to have a better handle on amplitude. Both show a small lead vort max over IA this afternoon which should be enough. Most everything seems to be in place for several strong tornadoes in the SPC's Tor risk Outlook before the overnight MCS sweeps east (initially).
Member Since: September 11, 2007 Posts: 142 Comments: 16478
399. beell
11:07 AM GMT on June 30, 2014

06Z Day 1 Probabilistic Tornado (click image for all Outlook graphics)

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT MON JUN 30 2014

VALID 301200Z - 011200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PORTIONS OF IA/MO/IL AND FAR SOUTHERN WI...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTH-CENTRAL PLAINS TO THE GREAT LAKES REGION...

...SUMMARY...
WIDESPREAD SEVERE THUNDERSTORMS CAPABLE OF LARGE HAIL...TORNADOES...AND SWATHS OF WIND DAMAGE ARE EXPECTED ESPECIALLY THIS AFTERNOON INTO TONIGHT ACROSS MUCH OF THE CORN BELT AND MIDWEST. ADDITIONAL SEVERE STORMS WILL BE POSSIBLE ACROSS THE SOUTH-CENTRAL PLAINS.

...SYNOPSIS...
THE LONGWAVE PATTERN WILL UNDERGO AMPLIFICATION DURING THE PERIOD TO THE NORTH OF A PERSISTENT UPPER RIDGE ACROSS THE SOUTHERN THIRD OF THE CONUS. IN PARTICULAR...A CLOSED LOW WILL MOVE SLOWLY EASTWARD OVER NORTHERN ONTARIO...WITH A SEASONALLY STRONG UPPER JET/AMPLIFYING SHORTWAVE TROUGH OVER THE NORTH-CENTRAL CONUS. AS A RESULT...HEIGHT FALLS AND INCREASINGLY STRONG CYCLONIC FLOW ALOFT WILL OVERSPREAD MUCH OF THE GREAT LAKES REGION/UPPER MIDWEST AND LOWER MO RIVER VALLEY THROUGH TONIGHT. A SOUTHEASTWARD-MOVING COLD FRONT ACROSS THE MIDDLE/LOWER MO VALLEY...UPPER MIDWEST...AND SOUTH-CENTRAL PLAINS WILL BE A GENERAL FOCUS FOR DEEP CONVECTIVE DEVELOPMENT AND ASSOCIATED SEVERE POTENTIAL.

...LOWER/MIDDLE MO VALLEY TO MIDWEST/UPPER GREAT LAKES...
AS COMPARED TO SUNDAY...UPPER-LEVEL FORCING FOR ASCENT WILL BE MUCH MORE CONSEQUENTIAL /ESPECIALLY BY LATE JUNE STANDARDS/ AND MORE OPTIMALLY TIMED RELATIVE TO PEAK HEATING. IN THE PRESENCE OF A VERY MOIST AIR MASS AND ROBUST INSTABILITY...LARGE HAIL...TORNADOES...AND POTENTIALLY WIDESPREAD DAMAGING WINDS ARE EXPECTED ACROSS THE REGION LATER TODAY AND TONIGHT.

EARLY DAY CONVECTION AND RELATED OUTFLOWS/CLOUD DEBRIS ONCE AGAIN ACCOUNT FOR SOME UNCERTAINTY RELATED TO SOME OF THE FORECAST DETAILS LATER TODAY. IN PARTICULAR...A REMNANT OVERNIGHT MCS COULD PERSIST EARLY TODAY ACROSS LOWER MI/NORTHERN INDIANA VICINITY...WHILE ADDITIONAL STORMS ARE LIKELY TO HAVE DEVELOPED ACROSS NEB/NORTHERN KS TO WESTERN IA THIS MORNING. ITS POSSIBLE THAT THESE STORMS ACROSS THE MIDDLE MO VALLEY COULD PERSIST/BECOME SURFACE-BASED DURING THE DAY UNDER THE INFLUENCE OF PERSISTENT WARM ADVECTION/DPVA. OF GREATER LIKELIHOOD MAY BE FOR THESE STORMS TO GENERALLY DECAY...WITH SUBSEQUENT SURFACE-BASED DEVELOPMENT DURING THE AFTERNOON AS HEIGHT FALLS OVERSPREAD THE REGION AND THE BOUNDARY LAYER AGGRESSIVELY DESTABILIZES.

OF NOTE RELATED TO NUMERICAL GUIDANCE...THE 00Z NAM/GFS APPEAR TO BE OVERLY INFLUENCED BY CONVECTIVE FEEDBACK ACROSS IA INTO THE UPPER MS VALLEY/LAKE MI VICINITY. WHILE REAL-WORLD FEEDBACK IS INDEED POSSIBLE GIVEN STRONG DIABATIC HEATING/RICH MOISTURE...THE EXACT RAMIFICATIONS ARE UNCERTAIN...AND THE EXTREME DETAILS OF THESE PROGGED DOWNSTREAM INFLUENCES /ROBUST MAGNITUDE OF THE PROGGED LOW-LEVEL WIND FIELD ETC./ ARE PROBABLY AT LEAST SOMEWHAT OVERDONE.

REGARDLESS...THE MOST PROBABLE SCENARIO IS FOR SURFACE-BASED STORMS TO DEVELOP/INTENSIFY THIS AFTERNOON...ESPECIALLY ACROSS IA/NORTHERN MO TO THE EAST OF AN ADVANCING SURFACE LOW AND NEAR THE SOUTHEASTWARD-MOVING COLD FRONT. GIVEN EARLIER EVENING /00Z/ OBSERVED REGIONAL RAOBS...A VERY MOIST AIR MASS WITH LOWER TO MIDDLE 70S SURFACE DEWPOINTS ARE EXPECTED TO PREVAIL WITHIN THE NEARBY WARM SECTOR. THIS WILL LIKELY CONTRIBUTE TO VERY STRONG DESTABILIZATION...IN THE ABSENCE OF OUTFLOWS AND LINGERING THICK CLOUD COVER...WITH AS MUCH AS 4000-5500 J/KG OF MLCAPE EXPECTED FROM KS INTO IA/NORTHERN MO AND IL. ROBUST INSTABILITY IN THE PRESENCE OF 40+ KT OF EFFECTIVE SHEAR WILL SUPPORT INTENSE SUPERCELLS AS THE INITIAL STORM MODE WITH A RISK OF VERY LARGE HAIL AND SOME TORNADOES. THE TORNADO POTENTIAL WILL BE INFLUENCED BY DIURNALLY STRONG LOW-LEVEL WINDS/SRH...ESPECIALLY NEAR/EAST OF THE DEVELOPING SURFACE LOW. GIVEN RELATIVELY STRONG FORCING FOR EARLY SUMMER...AND THE INFLUENCE OF THE COLD FRONT...UPSCALE QUASI-LINEAR GROWTH IS LIKELY TO OCCUR BY EARLY/MID-EVENING. AS SUCH...A POTENTIALLY WIDESPREAD DAMAGING WIND THREAT COULD EVOLVE ACROSS PORTIONS OF IA AND NORTHERN MO INTO IL/SOUTHERN WI AND POSSIBLE LOWER MI/NORTHERN INDIANA DURING THE EVENING/OVERNIGHT HOURS.

...SOUTH-CENTRAL PLAINS...
STRONG WARM SECTOR HEATING/FRONTAL UPLIFT SHOULD OVERCOME WARM MID-LEVEL TEMPERATURES/CAPPING WITH ISOLATED TO WIDELY SCATTERED STRONG TO SEVERE THUNDERSTORM DEVELOPMENT EXPECTED BY LATE AFTERNOON/EARLY EVENING. THE REGION WILL GENERALLY BE SOUTH OF THE STRONGER WESTERLIES ALOFT...BUT AROUND 30 KT OF EFFECTIVE SHEAR AND MODERATE TO STRONG BUOYANCY /NEAR THE FRONT AND DRYLINE/ WILL ALLOW FOR SUSTAINED/ORGANIZED MULTICELLS AND POSSIBLY A FEW SUPERCELLS. LARGE HAIL AND LOCALLY DAMAGING WINDS WILL BE THE PRIMARY HAZARDS.

...SOUTHERN APPALACHIANS/SOUTHEAST STATES...
WHILE VERTICAL SHEAR/OVERALL FORCING WILL BE WEAK...SUFFICIENT LOW-LEVEL LAPSE RATES AND BUOYANCY MAY EXIST FOR PULSE-TYPE STORMS CAPABLE OF MICROBURSTS THIS AFTERNOON.

..GUYER/DEAN.. 06/30/2014
Member Since: September 11, 2007 Posts: 142 Comments: 16478
398. beell
11:00 AM GMT on June 30, 2014
It's been hit or miss imo over the central and northern plains of late-but that looks like a winner.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
397. Thunderfan
10:58 AM GMT on June 30, 2014
Quoting beell:

06/30 08Z HRRR Simulated Reflectivity-Valid 5PM CDT Monday


It seems like those HRRR projections are amazingly accurate at times. They did an amazing job on my little ice storm here, for instance.
Member Since: April 14, 2012 Posts: 3 Comments: 790
396. beell
10:56 AM GMT on June 30, 2014

WPC Surface Forecast-Valid 7PM CDT Monday

Location of any residual outflows in relationship to the cold front may point towards the highest tornado risk. Current MCS over the upper midwest should clear the area in plenty of time to recharge.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
395. beell
10:47 AM GMT on June 30, 2014

06/30 08Z HRRR Simulated Reflectivity-Valid 5PM CDT Monday
Member Since: September 11, 2007 Posts: 142 Comments: 16478
394. beell
10:28 AM GMT on June 30, 2014

06/30 06Z GFS mb @ 4PM CDT

As the SPC mentioned, the models may be a bit overdone-but at least a 50 knot LLJ (somewhere in/near the red circle) should seal the deal on a HIGH risk day.
Member Since: September 11, 2007 Posts: 142 Comments: 16478
393. beell
11:34 PM GMT on June 29, 2014
SPC put it in a slightly different spot-but I like mine also.



Member Since: September 11, 2007 Posts: 142 Comments: 16478
392. beell
11:21 PM GMT on June 29, 2014
Hiya, bf. Thanks. There's the other boundary.


MESOSCALE DISCUSSION 1199
NWS STORM PREDICTION CENTER NORMAN OK
0606 PM CDT SUN JUN 29 2014

AREAS AFFECTED...ERN NEB THROUGH WRN IA AND EXTREME NWRN MO

CONCERNING...TORNADO WATCH 367...

VALID 292306Z - 300030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 367 CONTINUES.

SUMMARY...THREAT FOR VERY LARGE HAIL AND ISOLATED TORNADOES WILL PERSIST NEXT FEW HOURS FROM ERN NEB INTO WRN IA AND EXTREME NWRN MO. THE PRIMARY UNCERTAINTY IS HOW MANY STORMS WILL INITIATE...BUT POTENTIAL EXISTS FOR A FEW MORE STORMS TO DEVELOP THIS EVENING.

DISCUSSION...EARLY THIS EVENING A COUPLE OF STORMS INCLUDING A SUPERCELL AND A LEFT SPLIT HAVE DEVELOPED NEAR THE NEB/IA BORDER ON WHAT APPEARS TO BE A RESIDUAL OUTFLOW BOUNDARY. SEVERAL MESOSCALE BOUNDARIES RESIDE IN WARM SECTOR TO THE SOUTH OF A STATIONARY FRONT THAT EXTENDS FROM NERN NEB INTO NWRN IA AND SERN MN. THE ATMOSPHERE IN THIS REGION IS VERY UNSTABLE WITH 2000-3000 J/KG MLCAPE WITH A MODEST CAP. VWP AND PFC DATA SHOW STRONG SHEAR THROUGH 0-6 KM...BUT MODEST LOW-LEVEL SHEAR AND SMALL 0-1 KM HODOGRAPHS. THIS WIND PROFILE SUPPORTS SUPERCELLS WITH STRONGER MID-LEVEL UPDRAFT ROTATION...BUT STORMS MAY TAKE LONGER TO ORGANIZE IN LOWER LEVELS. NEVERTHELESS...GIVEN MAGNITUDE OF INSTABILITY AND POTENTIAL FOR STORMS TO INTERACT WITH EXISTING BOUNDARIES...TORNADOES REMAIN POSSIBLE IN ADDITION TO VERY LARGE HAIL. MOREOVER...SOME INCREASE IN 0-2 KM HODOGRAPHS SIZE MAY OCCUR THIS EVENING AS THE LLJ UNDERGOES SOME STRENGTHENING. VISIBLE IMAGERY CONTINUES TO SHOW ENHANCED CUMULUS OVER ERN NEB...AND A FEW OTHER STORMS ARE IN THE PROCESS OF DEVELOPING ACROSS WRN IA.

..DIAL.. 06/29/2014
Member Since: September 11, 2007 Posts: 142 Comments: 16478
391. Barefootontherocks
9:54 PM GMT on June 29, 2014
Glad they opted for a Tornado Watch. Love it. Not expecting much... but. lpl
The watch discussion:
...WDLY SCTD TSTMS EXPECTED TO FORM LATER THIS AFTN AND EVE WITH CONTINUED HEATING ALONG DIFFUSE W-E BOUNDARY ROUGHLY PARALLELING INTERSTATE ROUTE 80 OVER ERN NEB/WRN IA. LOW-LVL FLOW LIKELY WILL REMAIN WEAK GIVEN LINGERING PRESENCE OF E CNTRL KS MCS/MCV... AND UPR-LVL FORCING FOR ASCENT ESSENTIALLY NEUTRAL. BUT GIVEN DEGREE OF BUOYANCY /SBCAPE AROUND 4000 J PER KG/... RICH MOISTURE /PW AOA 1.50 INCHES/...40-50 KT WNWLY DEEP SHEAR... AND POTENTIAL FOR A FEW DISCRETE SUPERCELLS... A CONDITIONAL RISK FOR LARGE HAIL...DMGG WIND... AND TORNADOES WILL EXIST.
Please click for complete watch details


Sweet Sunday Drive. Be assured a girl remembers everything her father teaches her about safe driving.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
390. beell
8:13 PM GMT on June 29, 2014


MESOSCALE DISCUSSION 1195
NWS STORM PREDICTION CENTER NORMAN OK
0202 PM CDT SUN JUN 29 2014

AREAS AFFECTED...PORTIONS OF CENTRAL AND ERN NEB...WRN INTO CENTRAL IA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 291902Z - 292100Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...SEVERE THREAT WILL CONTINUE TO INCREASE THE NEXT FEW HOURS FROM CENTRAL NEB INTO WRN AND CENTRAL IA. LARGE HAIL...DAMAGING WINDS AND A TORNADO OR TWO WILL BE POSSIBLE INTO EARLY EVENING. AREA IS BEING MONITORED FOR WATCH ISSUANCE BY 21Z.

DISCUSSION...AS MORNING CLOUD COVER HAS THINNED AND SHIFTED EWD...TEMPERATURES HAVE WARMED INTO THE UPPER 70S AND LOW 80S...AND STRONG DESTABILIZATION WAS OCCURRING IN A MOIST AIRMASS /UPPER 60S TO LOW 70S DEWPOINTS/ BENEATH STEEP MIDLEVEL LAPSE RATES /AOA 7 DEG C PER KM PER 18Z OAX RAOB/. WHILE THE 18Z OAX AND TOP RAOBS INDICATED SOME INHIBITION STILL EXISTS...GREATER HEATING ACROSS CENTRAL NEB HAS OCCURRED AND LITTLE IF ANY CAPPING REMAINS. THIS IS EVIDENT IN AGITATED/CONGESTED CU FIELD ALONG THE EFFECTIVE FRONT/RESIDUAL OUTFLOW BOUNDARY WHERE CONVECTIVE INITIATION IS TRYING TO OCCUR AS NOTED BY WEAK ECHOS ON REGIONAL RADAR IN THE VICINITY OF BOONE COUNTY NEB.

ONCE INITIATION OCCURS...FAVORABLE SHEAR AND THERMODYNAMIC PROFILES WILL SUPPORT ROTATING UPDRAFTS WITH LARGE HAIL AND STRONG WINDS POSSIBLE. FURTHER EAST INTO ERN NEB/WRN IA...BACKED LOW LEVEL WINDS WILL BE MORE FAVORABLE FOR TORNADO POTENTIAL. WITH TIME...AS ADDITIONAL OUTFLOW BOUNDARIES ARE LAID OUT BY INDIVIDUAL STORMS...UPSCALE GROWTH INTO BOWING SEGMENTS WILL BE POSSIBLE...ENHANCING THE DAMAGING WIND THREAT.

..LEITMAN/CORFIDI.. 06/29/2014

In addition to the outflow boundary delineated on the MCD graphic, there may be an additional boundary that could offer a better orientation (E to W) and potential at or near the intersection in east central NE.



Member Since: September 11, 2007 Posts: 142 Comments: 16478
389. aquak9
8:07 PM GMT on June 29, 2014
doggie does a bikini dance
(yes, beell does remember)
but all of Jax won't see that dance
unless it's named in NOVEMBER
Member Since: August 13, 2005 Posts: 164 Comments: 25825
388. beell
6:59 PM GMT on June 29, 2014

Current RAP 12 hr 500 mb height change

...LARGE-SCALE FORCING FOR ASCENT ACROSS THE REGION WILL BE WEAK...WITH OVERALL HEIGHT RISES OCCURRING IN WAKE OF UPR MS TROUGH. THESE RISES WILL...HOWEVER...BE SOMEWHAT COUNTERACTED BY UPLIFT ASSOCIATED WITH DISTURBANCE NOW OVER WRN NEB...
Member Since: September 11, 2007 Posts: 142 Comments: 16478
387. beell
5:05 PM GMT on June 29, 2014
Thanks, doggie! I will try to compose a reply today. The rhyme will have to contain "Bikini Dance", "JAX", and "Arthur".
:)

Hi bf.
The ridge to the west may keep this system moving southward for a bit longer than modeled before a hook. So it may still pass near to the Bahamas.

For now...R wants to go for a drive!
Member Since: September 11, 2007 Posts: 142 Comments: 16478
386. beell
4:55 PM GMT on June 29, 2014

1630Z Day 1 Probabalistic tornado-click image for alll Outlook graphics

DAY 1 CONVECTIVE OUTLOOK NWS
STORM PREDICTION CENTER NORMAN OK
1129 AM CDT SUN JUN 29 2014

VALID 291630Z - 301200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF NEB...KS...IA...AND MO...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MODERATE RISK AREA FROM THE CNTRL PLNS INTO THE MID MS VLY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPR MS VLY...

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF VERY LARGE HAIL...A FEW TORNADOES...AND SWATHS OF DAMAGING WIND ARE POSSIBLE THIS AFTERNOON AND TONIGHT OVER PARTS OF THE CENTRAL PLAINS AND THE MID AND UPPER MISSISSIPPI VALLEYS.

...SYNOPTIC SETUP...
SEASONABLY STRONG WLY FLOW WILL PREVAIL THIS PERIOD FROM THE PACIFIC NW TO THE NRN PLNS/UPR MS VLY ON SRN SIDE OF NEARLY STNRY VORTEX OVER SRN MB. LEAD SHORTWAVE IMPULSE WITH THIS VORTEX...NOW OVER ERN WI...WILL CONTINUE ENE ACROSS MI LATER TODAY...FOLLOWED BY A WEAKER/SMALLER UPSTREAM DISTURBANCE NOW OVER CNTRL MN. FARTHER SW...SATELLITE INDICATES A POSSIBLE LOW-AMPLITUDE FEATURE NOW OVER WRN NEB THAT SHOULD CONTINUE ESE INTO THE LWR MO/MID MS VLYS BY EVE.

AT THE SFC...MAIN COLD FRONT WITH MB SYSTEM ATTM ARCS FROM N CNTRL MN S AND SW THROUGH CNTRL NEB INTO THE CNTRL HIGH PLNS. THE FRONT SHOULD ADVANCE STEADILY E ACROSS THE UPR MS VLY TODAY...WHILE THE SRN PART BECOMES STNRY OVER NEB AS A WEAK LEE LOW FORMS TNGT/EARLY MON ALONG EXISTING LEE TROUGH OVER NE CO/NW KS.

...CNTRL PLNS INTO MID/UPR MS VLYS TODAY THROUGH TNGT...
OVERALL SETUP OVER THIS REGION DURING THE NEXT 24 HRS WILL BE SUPPORTIVE OF MULTIPLE EPISODES/AREAS OF STRONG TO SVR TSTMS...WITH CONDITIONAL RISKS FOR VERY LARGE HAIL...DMGG WIND...AND TORNADOES. THE PATTERN WILL...HOWEVER...REMAIN COMPLICATED BY /1/ PRESENCE OF EXISTING CONVECTION AND /2/ THE FACT THAT UPR-LVL FORCING FOR ASCENT WILL BE SOMEWHAT FRACTURED AND/OR POSSIBLY NOT OPTIMALLY LOCATED/TIMED WITH RESPECT TO AREAS OF STRONGEST LOW-LVL CONVERGENCE.

GIVEN THE CONTINUED WEAKENING OF SCTD ON-GOING TSTMS...IT APPEARS THAT POCKETS OF STRONG INSTABILITY /SBCAPE AOA 4000 J PER KG/ SHOULD DEVELOP WITH SFC HEATING FROM S CNTRL NEB SWD INTO CNTRL/WRN KS...AND FROM ERN NEB ESEWD INTO PARTS OF IA...ERN KS...AND NW MO. LARGE-SCALE FORCING FOR ASCENT ACROSS THE REGION WILL BE WEAK...WITH OVERALL HEIGHT RISES OCCURRING IN WAKE OF UPR MS TROUGH. THESE RISES WILL...HOWEVER...BE SOMEWHAT COUNTERACTED BY UPLIFT ASSOCIATED WITH DISTURBANCE NOW OVER WRN NEB. IF SUSTAINED STORMS DO FORM...AND THIS SEEMS MORE LIKELY THAN NOT...40-50 KT WNWLY DEEP SHEAR ON SRN FRINGE OF MB LOW WILL BE FAVORABLE FOR SUPERCELLS. COUPLED WITH RICH MOISTURE AND STEEP LOW TO MID-LVL LAPSE RATES...THESE COULD YIELD LARGE HAIL/DMGG WIND. TORNADOES ALSO MAY OCCUR...ESPECIALLY LATE THIS AFTN AND EARLY TNGT WITH STORMS MOVING ALONG OUTFLOW BOUNDARY SEGMENTS LEFT BY EARLIER STORMS.

GIVEN THE STRENGTH OF SHEAR/BUOYANCY...AND THE LIKELIHOOD FOR MULTIPLE AREAS OF STORM GENERATION...SOME POTENTIAL WILL EXIST FOR UPSCALE DEVELOPMENT INTO MCSS. THESE COULD CONTAIN FOREWARD-PROPAGATING/BOWING SEGMENTS WITH DMGG WIND...ALTHOUGH EXPECTED FRACTURED NATURE OF LOW-LVL INSTABILITY FIELD LOWERS CONFIDENCE FOR ANY LONG-LIVED DERECHOS.

ADDITIONAL ROUNDS OF STORMS...SOME WITH SVR HAIL AND POSSIBLY WIND...MAY OCCUR LATE TNGT THROUGH EARLY MON OVER PARTS OF NEB AND NRN KS...WHERE MOIST/SLY LLJ WILL STRENGTHEN E OF LEE LOW IN RESPONSE TO AN ADDITIONAL UPSTREAM DISTURBANCE IN WLY FLOW ALOFT.


IN THE UPR MS VLY...A SEPARATE AREA OF STRONG TO SVR STORMS MAY EVOLVE WITH SFC HEATING THIS AFTN AHEAD OF MN UPR IMPULSE. DEEP SHEAR AND FORCING FOR ASCENT WILL BE STRONGER RELATIVE TO POINTS SOUTH...AND MID-LVL TEMPS WILL REMAIN COMPARATIVELY COOL. THE BOUNDARY LAYER...HOWEVER...BY COMPARISON WILL BE SOMEWHAT COOLER/DRIER. NEVERTHELESS...GIVEN 50 KT WSWLY DEEP SHEAR AND CONVERGENT LOW-LVL FLOW ALONG/AHEAD OF MN COLD FRONT...A CONDITIONAL RISK WILL EXIST FOR A FEW STORMS/POSSIBLE SUPERCELLS WITH SVR HAIL/WIND AND POSSIBLY A TORNADO ENE INTO THE MN ARROWHEAD...WI...AND PERHAPS WRN UPR MI..

...SRN HIGH PLNS LATE THIS AFTN AND EVE...
STRONG SFC HEATING ALONG DRY LINE/LEE TROUGH SHOULD FOSTER ISOLD TO WDLY SCTD HIGH-BASED TSTMS THIS AFTN/EVE...DESPITE ABSENCE OF ANY IDENTIFIABLE FEATURE TO ENHANCE LARGE-SCALE FORCING FOR ASCENT. DEEP/WELL-MIXED SUBCLOUD LAYER BENEATH 800-1500 J/KG MLCAPE COULD SUPPORT STG/ISOLD SVR GUSTS AND HAIL BEFORE STORMS WEAKEN WITH NOCTURNAL INCREASE IN CIN.

...ERN LWR MI...OH/TN VALLEYS THIS AFTN...
LARGE-SCALE ASCENT ACCOMPANYING LEAD UPR IMPULSE WILL CONTINUE TO SUPPORT AN ARC OF DIURNALLY-ENHANCED STORMS OVER ERN LWR MI TODAY...WHERE WIND PROFILES APPEARS SUFFICIENT FOR SOME DEGREE OF STORM ORGANIZATION/SUSTENANCE AND PERHAPS A FEW INSTANCES OF LOCALLY DMGG WIND.

FARTHER S...RELATIVELY WEAK CINH AND LIFT ALONG EXISTING OUTFLOW/DIFFERENTIAL-HEATING BOUNDARIES SHOULD PROMOTE SCTD TSTM CLUSTERS SWD INTO THE OH AND TN VLYS. MULTICELLULAR STORMS MAY YIELD A FEW DMGG GUSTS AND POSSIBLY MARGINALLY SVR HAIL.

..CORFIDI/MOSIER.. 06/29/2014
Member Since: September 11, 2007 Posts: 142 Comments: 16478
385. aquak9
3:46 PM GMT on June 29, 2014
Spaghetti on my east coast
Spaghetti on the shore
as long long as it's just noodles
and not Arthur at my door-

I'd really like some rainfall
and stormy weather, too
but clouds here are just puffy
skies are boring blue

A beast that's in the making?
That's a definite NOT
but I will tell it one thing-
"$%^t or get off the pot!!"

( aww heck, that's too good not to share- into the fray it goes- but it was for ya'll, first )


Member Since: August 13, 2005 Posts: 164 Comments: 25825
384. Barefootontherocks
3:35 PM GMT on June 29, 2014
"Looks like 91L wants to vacation in the Bahamas."
Oops. Guess not.


Happy Sunday.
bblbl
bf
Member Since: April 29, 2006 Posts: 151 Comments: 18530
383. Barefootontherocks
3:02 PM GMT on June 29, 2014
Hi. Good morning, bl.
Intersting discussion at the 08 outlook. Also noticed a new-to-me name yesterday. Seeing it again this morning, had to look. Dr. Jirak is science officer of SPC, apparently. Noticed the moderate risk (surprising) on your SPC blog graphic.

Was reading your 381 comment when you posted 382.
:)

Happy you found an okay vehicle. Safe travels to R!

Looks like 91L wants to vacation in the Bahamas.
Member Since: April 29, 2006 Posts: 151 Comments: 18530
382. beell
2:38 PM GMT on June 29, 2014

click image for all 13Z Day 1 graphics

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 AM CDT SUN JUN 29 2014

VALID 291300Z - 301200Z

...THERE IS A MDT RISK OF SVR TSTMS PORTIONS SERN NEB...NERN KS...NRN MO...CENTRAL/SRN IA...

...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM PORTIONS KS/NEB TO WI/IL....

...SUMMARY...
SEVERE THUNDERSTORMS CAPABLE OF PRODUCING VERY LARGE HAIL...A FEW TORNADOES...AND SWATHS OF DAMAGING WINDS ARE POSSIBLE ESPECIALLY THIS AFTERNOON AND TONIGHT ACROSS PORTIONS OF THE CENTRAL PLAINS TO THE MIDDLE AND UPPER MISSISSIPPI VALLEY.

...SYNOPSIS...
MOST PROMINENT UPPER-AIR FEATURE FOR THIS FCST PERIOD WILL BE CYCLONE LOCATED ATTM OVER SRN PORTIONS SK/MB BORDER...AND FCST TO MEANDER SLOWLY NEWD OVER LAKE WINNIPEG. AROUND SRN RIM OF THAT FEATURE...CYCLONIC FLOW WILL PREVAIL OVER MOST OF UPPER MIDWEST. SHORTWAVE TROUGH NOW OVER UPPER MS VALLEY IS FCST TO DEAMPLIFY CONSIDERABLY AS IT EJECTS NNEWD ACROSS LS TO NWRN ONT. WEAKER/SECONDARY PERTURBATION -- NOW EVIDENT IN MOISTURE-CHANNEL IMAGERY OVER ERN SD -- IS FCST TO MOVE RAPIDLY ENEWD ACROSS NRN MN TO NWRN ONT BY 00Z. NET EFFECT OVER MUCH OF MDT RISK AREA WILL BE HEIGHT RISES.

AT SFC...PRIMARY CYCLONE WAS ESSENTIALLY STACKED WITH UPPER LOW OVER MB...COLD FRONT EXTENDING SEWD OVER WRN MN THEN SWWD ACROSS CENTRAL NEB AND BECOMING QUASISTATIONARY OVER EXTREME ERN CO. FRONT IS FCST TO MOVE EWD OVER MN AND DRIFT EWD OR REMAIN NEARLY STATIONARY OVER MOST OF CENTRAL PLAINS. WEAK/SECONDARY LOW OVER SERN CO MAY MOVE NEWD LATE IN PERIOD AND DEEPEN OVERT WRN/NRN KS.

...CENTRAL PLAINS TO MID/UPPER MS VALLEY...
COMPLEX...RATHER MESSY AND MULTI-EPISODE CONVECTIVE SCENARIO ALREADY IS APPARENT OVER THIS REGION...WITH SEVERAL ROUNDS OF TSTMS ONGOING AND FCST ALONG/AHEAD OF SFC COLD FRONT CUMULATIVELY CONTRIBUTING TO SVR RISKS. THIS IS TRUE BOTH IN ACTUAL ATMOSPHERE AND IN VARIOUS OPERATIONAL AND MESOSCALE/CONVECTION-ALLOWING MODELS WHOSE SOLUTIONS INCONSISTENTLY RESOLVE CURRENT TRENDS. CONSENSUS APCH MODULATED WITH ONGOING ACTIVITY STILL POINTS TOWARD MDT-RISK AREA AS BEING MOST FAVORABLE...WITH ONLY MINOR ADJUSTMENTS FROM PRIOR FCST.

KS/NEB TSTMS ONGOING THIS MORNING MAY PRODUCE SPORADIC LARGE HAIL AND DAMAGING GUSTS...HOWEVER MOST OF THIS ACTIVITY SHOULD WEAKEN BY LATE MORNING IN STEP WITH LESSENING OF SUPPORTIVE LLJ AND RELATED STORM-RELATIVE INFLOW. HOWEVER...ANY UPSCALE/COLD-POOL GROWTH...PARTICULARLY WITH KS CONVECTION...MAY PROLONG IT FOR A COUPLE EXTRA HOURS THROUGH FORCED ASCENT OF FAVORABLY HIGH-THETAE LOW-LEVEL AIR. REF SPC MESOSCALE DISCUSSION 1194 FOR ADDITIONAL/NEAR-TERM INFO.

GREATER SVR THREAT SHOULD BE THIS AFTN INTO TONIGHT. FOR NOW...AND WITH SOME RELUCTANCE...WE ARE RETAINING PROBABILITIES THAT DRIVE CATEGORICAL MDT RISK...GIVEN 1. STRONGLY FAVORABLE FCST CAPE/SHEAR PARAMETER SPACE OVER OUTLOOK AREA THIS AFTN... 2. POTENTIAL FOR OUTFLOW AND/OR DIFFERENTIAL-HEATING BOUNDARIES RELATED TO ONGOING CONVECTION TO SERVE AS FOCI FOR TSTM INITIATION/MAINTENANCE ALONG NRN/WRN MARGINS OF OUTLOOK AREAS...AND 3. RELATED POTENTIAL FOR ANY CONVECTION THAT DOES DEVELOP OR MOVE INTO OUTLOOK AREA TO PRODUCE SIGNIFICANT SVR AND/OR GROW UPSCALE RAPIDLY INTO MCS...WITH SUPERCELLS POSSIBLE IN INTERIM...OFFERING COLLECTIVE THREAT FOR ALL MODES OF SVR.

PRESENCE OF UPPER-60S/LOWER-70S F SFC DEW POINTS WHERE STG HEATING DOES OCCUR WILL SUPPORT 2000-3000 J/KG MLCAPE...LOCALLY HIGHER...AMIDST RELATIVELY LOW LCL HEIGHTS. MEANWHILE BELT OF 55-65-KT 500-MB WINDS AND 60-90-KT 250-MB FLOW ON SRN RIM OF CYCLONIC JET CORE WILL ENHANCE DEEP SHEAR. 40-55 KT EFFECTIVE-SHEAR MAGNITUDES SHOULD BECOME COMMON WITHIN HIGH-CAPE AREAS. THESE CONDITIONS WILL SUPPORT AGGRESSIVE GROWTH IN INTENSITY AND COVERAGE OF ANY SUSTAINED CONVECTION THAT CAN OCCUR IN THIS AIR MASS.

THAT SAID...POTENTIALLY CRUCIAL CAVEATS AND UNCERTAINTIES ARE APPARENT...WHICH MAY CONTRIBUTE TO LESSENING OF THREAT OVER SOME PARTS OF THIS AREA. LACK OF SUBSTANTIAL UPPER-LEVEL SUPPORT...AND INDEED RISING HEIGHTS AS NOTED ABOVE...ARE ONE CONCERN. CLOUDS RELATED TO PERSISTENT/ONGOING CONVECTION OVER NWRN KS AND PERHAPS NEWLY DEVELOPED ACTIVITY OVER CENTRAL NEB MAY RESTRICT OR DELAY DIABATIC HEATING DOWNSTREAM WITH RESPECT TO UPPER-LEVEL FLOW...ACROSS PORTIONS NRN KS/NWRN MO/SERN NEB.

...SRN HIGH PLAINS...
LARGE-SCALE/UPPER-LEVEL SUPPORT WILL BE WEAK TO NIL OVER THIS AREA...WHICH ALSO IS EXPECTED TO EXPERIENCE HEIGHT RISES ALOFT. NONETHELESS...VERY STG DIABATIC SFC HEATING IS LIKELY INVOF DRYLINE THAT WILL MIX SOMEWHAT EWD FROM CURRENT POSITION OVER ERN NM. ISOLATED TO WIDELY SCATTERED...HIGH-BASED TSTMS MAY DEVELOP THIS AFTN...PERSISTING INTO EARLY EVENING BEFORE SFC COOLING SUBSTANTIALLY BOOSTS CINH. STEEP DEEP-TROPOSPHERIC LAPSE RATES AND DEEP/WELL-MIXED SUBCLOUD LAYERS ARE EXPECTED BENEATH 800-1500 J/KG MLCAPE. STG/ISOLATED SVR GUSTS AND HAIL ARE POSSIBLE WITH THIS RELATIVELY TRANSIENT REGIME.

...LOWER MI...OH/TN VALLEYS...
RELATIVELY WEAK CINH AND LIFT ALONG ASSORTED OUTFLOW/DIFFERENTIAL-HEATING BOUNDARIES WILL SUPPORT POTENTIAL FOR SCATTERED TSTMS IN CLUSTERS THIS AFTN INTO EVENING. PRIMARY MODE SHOULD BE MULTICELLULAR WITH DAMAGING GUSTS AND ISOLATED SVR HAIL PSBL.

..EDWARDS/JIRAK.. 06/29/2014

Member Since: September 11, 2007 Posts: 142 Comments: 16478
381. beell
4:08 AM GMT on June 29, 2014
Got it done, bf!

I think she would have went for a shoe box on wheels if it was the right color and did not look like a "Mom car".
We did ok!

MDT Risk up for tomorrow...

Hi Linda!

Night, ya'll.

Member Since: September 11, 2007 Posts: 142 Comments: 16478
380. Barefootontherocks
5:09 PM GMT on June 28, 2014
Ha! At present, WU tropics page has 91L moving 25 mph to SE.
...

Looks like there is a MCD out for what SPC thought might be the most convection-inclined area. Only 40% chance for a watch. Please click for discussion.


Not to worry, bl. I think the convective arena will understand what you have to do is most important. :)


(Hi, Thoughtsteader.)
Member Since: April 29, 2006 Posts: 151 Comments: 18530

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