Record-Warm Subsurface Pacific Waters May Bring Moderate to Strong El Niño Event

By: Michael Ventrice , 3:19 PM GMT on April 04, 2014

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Today's guest blog post is by Dr. Michael Ventrice, an operational scientist for the Energy team at Weather Services International (WSI). This is a follow-up post to the one he did on February 21 on the progress of El Niño. Today's post is very technical! - Jeff Masters

There have been tremendous changes in the Pacific Ocean over the past two months which continue to favor a moderate to strong El Niño event later this spring and summer. Since my previous post on February 21, NOAA's Climate Prediction Center (CPC) has issued an El Niño watch.

To begin, we are currently observing what looks to be the strongest downwelling oceanic Kelvin wave event since satellite records began in the 1970s. This still needs to be verified in reanalysis, but a large swath of 6°C (11°F) ocean temperature anomalies at a depth of 100 - 200 meters (Figure 1) clearly illustrates the significance of this event. To review, oceanic Kelvin waves travel only from west to east at extremely slow speeds (2-3 m/s). These waves have been alluded to as the facilitators of El Niño. There are two phases of an oceanic Kelvin wave, the “Upwelling” phase and the “Downwelling” phase. The Upwelling phase of an oceanic Kelvin wave pushes colder water from the sub-surface towards the surface, resulting in cooling at the surface. The Downwelling phase is the opposite, where warmer waters at the surface of the West Pacific warm pool are forced to sink, resulting a deepening of the thermocline and net warming in the sub-surface.


Figure 1. Departure of ocean temperature from average along the Equator in the Pacific Ocean on March 29, 2014 (top), shows a large area of 6°C (11°F) ocean temperature anomalies at a depth of 100 - 200 meters. A time lapse is available here. Image credit: NOAA/CPC.

In the West Pacific, the thermocline is rising in response to strong upwelling (cold ocean temperature anomalies near the surface). In the central and eastern Pacific, the thermocline is deepening as the warm pool has begun to rapidly shift towards the Date Line. An enlightening time lapse can be found on the NOAA/CPC webpage. Note the lens of colder than average ocean temperature anomalies at the surface in the far eastern Pacific. This can be attributed to a surge in the Easterly trade winds over the eastern equatorial Pacific, which pushes water away from the coast, resulting in some upwelling off the west coast of South America. The surge in the trade winds is just an expression of atmospheric processes occurring in the tropics at intra-seasonal (weekly) timescales. Nevertheless, it is evident that the entire West Pacific Warm Pool has begun to shift eastward, and there is a large adjustment in the Pacific Ocean currently underway.

That being said, we still need to see some favorable atmospheric forcing this month to continue the forward advancement of a full-basin El Niño. In particular, west-to-east blowing winds along the Equator are needed to keep pushing warm water eastwards towards South America. Keeping this in mind, there are some signs of an upcoming period of westerly wind bursts along the equatorial Central Pacific in the next few weeks.



Figure 2. Rainfalls rates over the Indian Ocean (shaded colors), departure of the winds at 200 mb from average (arrows), and Kelvin filtered velocity potential at 200 mb (VP200, contours.) Image credit: Michael Ventrice.

An exceptionally strong atmospheric convectively coupled Kelvin wave (CCKW) is currently propagating across the equatorial Indian Ocean. IMPORTANT: An atmospheric CCKW is DIFFERENT than an oceanic Kelvin wave since atmospheric CCKWs are stratospheric waves in the *atmosphere* that are confined to just the equatorial band. Thus we cannot experience a CCKW passage in North America. CCKWs often couple with thunderstorm activity within the troposphere in the tropics. In addition, CCKWs in the atmosphere are non-dispersive in theory, so they can make many circuits around the globe before attenuating from external forcing such as friction; oceanic Kelvin waves can only travel the distance of whatever basin they are in (in this case, the Pacific). However, *both* atmospheric CCKWs and oceanic Kelvin waves propagate from west to east only.



Figure 3. A time-longitude plot of unfiltered VP200 anomalies (shaded) with Kelvin filtered VP200 anomalies (contours; dashed contours represent the upper-level divergent phase of the CCKW or its convectively active phase) illustrates the non-dispersive nature of this CCKW, as it makes a complete circuit around the globe. Image credit: Michael Ventrice.



Figure 4. GFS model forecast for April 6, 2014. Six-hour precipitation rates are shaded. Often during and up to a few days after the passage of a strong CCKW, tropical cyclones can develop on either side of the Equator, depending on the season. An example can be seen over the Southern Indian Ocean this week, where the GFS model is forecasting the development of a tropical “gyre” that could become a tropical depression. Note the equatorial westerlies are a component of the anatomy of the CCKW circulation itself.

The forecast calls for this Indian Ocean CCKW to push across the Date Line during mid-April. This would be a time when we might see another period of westerly winds develop across the equatorial Central Pacific--favorable atmospheric conditions for a full-basin El Niño to emerge. The anticipated westerly wind burst in mid-April may be composed of individual tropical cyclones, or extra-tropical waves intruding the tropics.

In addition to the CCKW itself, there are higher than average probabilities of another developing Madden Julian Oscillation (MJO) to emerge over the West Pacific following the passage of this strong CCKW, in mid-to-late April. A great deal of my graduate study work focused on CCKW-MJO interactions and the plot below is from Ventrice et al. (2012), which is of a time-longitude composite plot of unfiltered VP200 anomalies (shaded), Kelvin filtered outgoing long wave radiation (OLR) anomalies (black contours), and MJO filtered OLR anomalies (orange contours). From selecting only dates where a strong CCKW passed the eastern tropical Atlantic, a lagged composite approach from these dates reveal a remarkable picture. Once the CCKW passes across Africa to over the Indian Ocean, we often observe a developing MJO event over the Indian Ocean that then propagates eastward across the Pacific region thereafter. There are increased chances of a similar scenario to play out over the next few weeks.



Why does this matter for El Niño? Well, within and following the passage the convectively active phase of the MJO, we often observe an increased number of West Pacific typhoons and low-level westerly wind flow. This is what is likely needed to continue the eastward advancement of the West Pacific Warm Pool this spring, and provides more evidence for a full-basin El Niño event to emerge later this spring in through summer. Furthermore, it is important to note that the latest climate model forecasts are now more aggressive with the amplitude of the potential emerging El Niño. This can be seen in both the ECMWF and CFSv2 Niño3.4 forecasts. For the purpose of illustration, below is the CFSv2 model forecast from mid-February 2014:



And here is the CFSv2 model forecast from Early April 2014:


Nearly a +0.5°C adjustment has been made in just one month for the June-July-August period and beyond, indicating that the model is even more bullish on the El Niño this spring in through summer.

Bottom Line: The Pacific Ocean continues to show signs of a developing moderate to strong El Niño event. During strong full-basin El Niño’s, we often observe cooler than average temperatures in summer across the eastern two thirds of the U.S., and lower than average Atlantic hurricane activity.

Michael Ventrice

Dr. Michael Ventrice is an operational scientist for the Energy team at Weather Services International (WSI), who provide market-moving weather forecasts and cutting-edge meteorological analysis to hundreds of energy-trading clients worldwide. Follow the WSI Energy Team on Twitter at @WSI_Energy and @WSI_EuroEnergy.

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1059. nola70119
5:32 AM GMT on April 07, 2014
Looks like something good headed this way........ETA?
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1058. Patrap
3:19 AM GMT on April 07, 2014


Member Since: July 3, 2005 Posts: 428 Comments: 129805
1057. Jedkins01
3:03 AM GMT on April 07, 2014
.
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1056. PedleyCA
2:57 AM GMT on April 07, 2014
http://cdn.tribtv.com/ktla/wx/images/Dot_Com_IE_7Da y_Large.JPG

82.3F here today and getting warmer tomorrow.
Member Since: February 29, 2012 Posts: 0 Comments: 6223
1055. WunderAlertBot (Admin)
2:53 AM GMT on April 07, 2014
JeffMasters has created a new entry.
1054. sar2401
2:50 AM GMT on April 07, 2014
Quoting GeoffreyWPB:


Surprised the Undertaker agreed to this! Vince must have paid him big bucks. My guess is he will retire tomorrow on Raw.

This is that wrestler guy with the long stringy hair, right? Has he ever washed it or does it still look the same. :-)
Member Since: October 2, 2004 Posts: 0 Comments: 17327
1053. Jedkins01
2:50 AM GMT on April 07, 2014
Quoting 1000. Ameister12:
00z Jackson, MS sounding.

Impressive to say the least.


While it might be impressive, I'm not seeing any signs of rotating supercells yet, just a lot of heavy rain and general thunderstorms with an occasional severe cell.
Member Since: August 21, 2008 Posts: 0 Comments: 8015
1052. sar2401
2:47 AM GMT on April 07, 2014
Quoting Jedkins01:


Yeah power lines under trees often leads to power outages, that's for sure.

Wait, so are you implying Florida doesn't have forests, you're joking right?

If not, evidently you have not been to FL, I've been through much of the deep south including Alabama, they do have dense forests, but are not as dense as forests can be here, lol. You need a machete like they do in the tropics to get around, and we get massive oaks, pines, and Cyprus trees that grow huge in width and height.

Poor soil condition limits the height of the trees some, but areas that have really tall trees where the soil is a little more rich, like around swamp areas.



No, just more forest land (23 million acres vs 14 million acres) even though Florida is slightly larger than Alabama in land area. More trees to fall over so a better chance of catching a power line...or my cable that's stapled to one of them. We have a jungle too but it's made up of that danged kudzu. You can't even walk through most of the woods without getting trapped by that stuff. Another agricultural experiment gone haywire.
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1051. Patrap
2:47 AM GMT on April 07, 2014
New Orleans
NEXRAD Radar

Velocity Azimuth Display Wind Profile ° Elevation
Range 124 NMI



Member Since: July 3, 2005 Posts: 428 Comments: 129805
1050. Patrap
2:30 AM GMT on April 07, 2014


Member Since: July 3, 2005 Posts: 428 Comments: 129805
1049. ncstorm
2:28 AM GMT on April 07, 2014
SPC AC 070105

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0805 PM CDT SUN APR 06 2014

VALID 070100Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PART OF THE LOWER MS
VALLEY AND CENTRAL GULF COAST STATES...

...LA/MS/AL/WRN FL PANHANDLE...
60-90 METER 500 MB HEIGHT FALLS SPREADING INTO THE LOWER MS VALLEY
AND LOW LEVEL WAA WILL CONTINUE TO SUPPORT TSTM DEVELOPMENT THIS
EVENING INTO THE OVERNIGHT PERIOD ACROSS THE LOWER MS VALLEY AND
CENTRAL GULF COAST STATES...AS A SHORTWAVE TROUGH TRACKS FROM THE
SRN PLAINS TO THE OZARKS REGION. THIS WILL SUPPORT AN AREA OF LOW
PRESSURE DEEPENING AS IT TRACKS FROM THE UPPER TX COAST TO WRN OR
MIDDLE TN BY 12Z MONDAY. 00Z SOUNDINGS INDICATED RELATIVELY
SUBSTANTIAL LOW LEVEL MOISTENING HAS OCCURRED FROM LA INTO MS AND AL
SINCE 12Z TODAY...WHILE SURFACE OBSERVATIONS SHOWED SURFACE
DEWPOINTS IN THE LOWER 70S HAVE MOVED INLAND ACROSS SRN PARTS OF LA.
A CONTINUED RETURN OF HIGHER THETAE AIR IS EXPECTED INTO THE LOWER
MS VALLEY AND CENTRAL GULF COAST STATES THROUGH THIS FORECAST PERIOD
RESULTING IN LOW LCLS. ALTHOUGH INSTABILITY WILL TEND TO REMAIN
MARGINAL WITH NWD EXTENT AWAY FROM THE COAST...LOCATIONS WITH
SURFACE DEWPOINTS INTO THE MIDDLE 60S COMBINED WITH STRENGTHENING
DEEP LAYER WIND FIELD WILL HAVE AN INCREASED TORNADO THREAT AS LOW
LEVEL AND DEEP LAYER SHEAR INCREASE. A FEW STRONG TORNADOES WILL BE
POSSIBLE THIS EVENING AND OVERNIGHT INTO EARLY MONDAY MORNING ACROSS
SERN LA...SRN MS...AND SWRN AL WHERE MOISTENING WILL BE THE GREATEST
AND LARGE HODOGRAPH CURVATURE IS EXPECTED AS THE SLY LLJ
STRENGTHENS.

...ERN AR/FAR NRN MS INTO WRN TN...
AN INCREASE IN FORCING FOR ASCENT LATE IN THIS FORECAST PERIOD IS
EXPECTED ACROSS ERN AR INTO FAR NRN MS AND WRN TN WITHIN THE EXIT
REGION OF A STRENGTHENING SSWLY 500 MB JET ACCOMPANYING THE NEWD
MOVING SHORTWAVE TROUGH. THIS...COMBINED WITH DPVA...STEEPENING
MIDLEVEL LAPSE RATES /7-7.5 C PER KM/...MUCAPE 700-900 J/KG AND
RELATIVELY STRONG CLOUD-BEARING SHEAR SUGGEST A FEW STRONGER CORES
WILL BE CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL. THIS ACTIVITY
WILL BE ELEVATED WITH POINT FORECAST SOUNDINGS SHOWING THE BASES
ROOTED BETWEEN 700-850 MB.

...PARTS OF THE NRN/CENTRAL PLAINS TO THE PERMIAN BASIN IN TX...
LOSS OF DAY TIME HEATING IS EXPECTED TO SUPPORT AN OVERALL DECREASE
IN TSTM POTENTIAL ACROSS THE MIDDLE PART OF THE LOWER 48 STATES.
FOR SHORT TERM FORECAST DETAILS FOR THE PERMIAN BASIN WHERE THERE
HAVE BEEN A FEW STRONGER STORMS...REFER TO SPC MESOSCALE DISCUSSION
#299.

..PETERS.. 04/07/2014

CLICK TO GET WUUS01 PTSDY1 PRODUCT

NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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1048. Patrap
2:24 AM GMT on April 07, 2014
It be like waiting for a first feeder band, you know when it gets here trouble iz behind it.



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1047. NCstu
2:21 AM GMT on April 07, 2014
Any excitement over your way Pat?
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1046. Patrap
2:21 AM GMT on April 07, 2014
Temp 73F

Dewpt 71
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1045. Thrawst
2:17 AM GMT on April 07, 2014
Quoting 1042. Ameister12:
Dew points are quickly increasing in Hattiesburg, MS. 57 a little over an hour ago; now it's 68. Also, the dew point in NOLA is 71. Nice fuel for the intensifying bands to the west.


Welcome the warm front. Give it a "warm" welcome.
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1044. Jedkins01
2:15 AM GMT on April 07, 2014
Quoting 837. sar2401:

Well, we do have a thing called forests up here. :-) Seriously, the woods are a lot more dense, and we have a lot more tall trees. Because this area is rural, we have lots of power lines that literally run through the woods. Alabama Power does clear the right of way of larger trees for high voltage lines but it's the smaller lines that tend to get taken out by trees, and when enough of them go down, we eventually lose a connection to the substation, even though the actual break might be 10 miles away. We have two problem trees - the native live oaks and the farmed Southern Yellow Pines. The live oaks are well rooted but the branches (some of which are as large as the trunk of an otherwise pretty good sized tree) get rotten and break in strong winds. The pine are regularly burned to decrease the understory and encourage the trees to grow tall and straight. They are very shallow rooted and come down easily in high winds. It's not just power lines either. Our cable is literally stapled to trees running through the woods so we always lose the cable in a storm. This is the only place I've ever seen that takes fiber optic cable and staples it to trees. As far as underground transformer problems, we don't have to worry about that, since we don't have any. If power or communications gets here, it's either on a pole or stapled to a tree. Living in a small town is great...most of the time. :-)


Yeah power lines under trees often leads to power outages, that's for sure.

Wait, so are you implying Florida doesn't have forests, you're joking right?

If not, evidently you have not been to FL, I've been through much of the deep south including Alabama, they do have dense forests, but are not as dense as forests can be here, lol. You need a machete like they do in the tropics to get around, and we get massive oaks, pines, and Cyprus trees that grow huge in width and height.

Poor soil condition limits the height of the trees some, but areas that have really tall trees where the soil is a little more rich, like around swamp areas.


Member Since: August 21, 2008 Posts: 0 Comments: 8015
1043. GeoffreyWPB
2:14 AM GMT on April 07, 2014
Quoting 1036. Tazmanian:



For the 1st time in WWE history the undertaker lost


Surprised the Undertaker agreed to this! Vince must have paid him big bucks. My guess is he will retire tomorrow on Raw.
Member Since: September 10, 2007 Posts: 0 Comments: 11538
1042. Ameister12
2:11 AM GMT on April 07, 2014
Dew points are quickly increasing in Hattiesburg, MS. 57 a little over an hour ago; now it's 68. Also, the dew point in NOLA is 71. Nice fuel for the intensifying bands to the west.
Member Since: August 9, 2009 Posts: 10 Comments: 5082
1041. JRRP
2:10 AM GMT on April 07, 2014
Quoting GTstormChaserCaleb:
I'll take the Undertaker. I remember the days of Hollywood Hogan, Macho Man Randy Savage, the Giant, Sting, Kevin Nash, Booker T, Goldberg, Stone Cold Steve Austin, etc...

yea good times... but taker lost omg
Member Since: August 16, 2007 Posts: 0 Comments: 6213
1040. Patrap
2:05 AM GMT on April 07, 2014
Quoting 1034. Birthmark:

You can't post the Big Board on the public internet!


I got a Waiver, and it took a lotta pull too.



Member Since: July 3, 2005 Posts: 428 Comments: 129805
1039. TylerStanfield
2:00 AM GMT on April 07, 2014
Quoting 1030. TimSoCal:


So my apologies, but I don't really know how to read this map. If the value is positive, the winds are reversed from normal?

If it's negative, the winds are reversed from normal.
Looking into the Atlantic, the zonal winds would be to the west, as that is what the typical flow of trades are in the Atlantic, from the East.
So when the chart shows negative, it means the winds are much slow, if not, from the opposite direction.
EDIT:
Sorry, wasn't clear on my wording.
The trades are from the East moving to the West.
Member Since: June 2, 2013 Posts: 9 Comments: 1402
1038. Ameister12
1:59 AM GMT on April 07, 2014
These cells are going up pretty quickly. Keep an eye on them.
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1037. Patrap
1:58 AM GMT on April 07, 2014
I hope no Ego's were sprained
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1036. Tazmanian
1:57 AM GMT on April 07, 2014
Quoting 1012. JRRP:

i´m watching Undertaker vs Brock Lesnar now




For the 1st time in WWE history the undertaker lost
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
1035. GTstormChaserCaleb
1:56 AM GMT on April 07, 2014
Quoting 1012. JRRP:

i´m watching Undertaker vs Brock Lesnar now

I'll take the Undertaker. I remember the days of Hollywood Hogan, Macho Man Randy Savage, the Giant, Sting, Kevin Nash, Booker T, Goldberg, Stone Cold Steve Austin, etc...
Member Since: June 30, 2013 Posts: 12 Comments: 8774
1034. Birthmark
1:56 AM GMT on April 07, 2014
Quoting 1031. Patrap:



You can't post the Big Board on the public internet!
Member Since: October 30, 2005 Posts: 7 Comments: 5469
1033. TylerStanfield
1:55 AM GMT on April 07, 2014
I sure hope this forecast by the GFS comes to fruition. (Paying attention to only Texas)
Member Since: June 2, 2013 Posts: 9 Comments: 1402
1032. Grothar
1:54 AM GMT on April 07, 2014
Quoting 1007. Patrap:
I member when Gro first said, "Dark Matter won't matter."

Right after Helium came to be.

Then Lunch,the first lunch,but it was a limited Menu, No herring yet.


Helium came in handy when I had to sing "We are the Lollipop Guild"
Member Since: July 17, 2009 Posts: 71 Comments: 27208
1031. Patrap
1:53 AM GMT on April 07, 2014


Member Since: July 3, 2005 Posts: 428 Comments: 129805
1030. TimSoCal
1:50 AM GMT on April 07, 2014
Quoting 1024. TylerStanfield:



The significant warming trend has paused for now, but in about two weeks, another warming trend should commence.


Westerly trades should prevail once again, according to the CFS, allowing for further warming .


So my apologies, but I don't really know how to read this map. If the value is positive, the winds are reversed from normal?
Member Since: July 9, 2013 Posts: 0 Comments: 832
1029. hurricanes2018
1:50 AM GMT on April 07, 2014
BMX issues Severe Thunderstorm Warning for Pickens [AL] till 9:30 PM CDT
Member Since: March 12, 2013 Posts: 110 Comments: 105690
1028. Grothar
1:49 AM GMT on April 07, 2014
Quoting 1019. docrod:


calling Slim Pickens !!


lol. My favorite scene.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
1027. GTstormChaserCaleb
1:49 AM GMT on April 07, 2014
Quoting 1024. TylerStanfield:



The significant warming trend has paused for now, but in about two weeks, another warming trend should commence.


Westerly trades should prevail once again, according to the CFS, allowing for further warming .
Looks like wind shear is expected to stay low in the Atlantic during this time.
Member Since: June 30, 2013 Posts: 12 Comments: 8774
1026. Grothar
1:48 AM GMT on April 07, 2014
Quoting 1024. TylerStanfield:



The significant warming trend has paused for now, but in about two weeks, another warming trend should commence.


Westerly trades should prevail once again, according to the CFS, allowing for further warming .


I was reading about the pause. The westerlies were bowing pretty good for awhile. I think I remember in 1997 that they really didn't give much warning it would be as bad as it was. Usually at the end of April, I do believe as you said, they will increase again. Can't wait for April 10.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
1025. Patrap
1:48 AM GMT on April 07, 2014
Stay ALERT



MESOSCALE DISCUSSION 0300
NWS STORM PREDICTION CENTER NORMAN OK
0748 PM CDT SUN APR 06 2014

AREAS AFFECTED...SW AND S CENTRAL LA

CONCERNING...TORNADO WATCH 64...

VALID 070048Z - 070215Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 64 CONTINUES.

SUMMARY...THE THREAT FOR TORNADOES APPEARS TO BE INCREASING SOME
COMPARED TO THE PAST FEW HOURS...WITH NEW SURFACE-BASED THUNDERSTORM
DEVELOPMENT ACROSS S CENTRAL LA.


DISCUSSION...THE 00Z LCH SOUNDING REVEALED MLCAPE NEAR 1800 J/KG
WITHIN THE WARM SECTOR...WITH SURFACE DEWPOINTS OF 70-72 F BELOW 7
C/KM MIDLEVEL LAPSE RATES. THE RECENT DEVELOPMENT OF APPARENTLY
SURFACE-BASED STORMS NEAR LAFAYETTE MAY BE SIGNALING A RELATIVE
INCREASE IN THE TORNADO RISK...COINCIDENT WITH THE WARM SECTOR
CONTINUING TO EXPAND INLAND. GIVEN THE RICH MOISTURE AND MODERATE
BUOYANCY...STORMS INTERACTING WITH THE WARM FRONT /AND ZONE OF
ENHANCED LOW-LEVEL SHEAR/ WILL HAVE THE POTENTIAL TO PRODUCE
TORNADOES...IN ADDITION TO DAMAGING GUSTS AND ISOLATED LARGE HAIL.

..THOMPSON/GUYER.. 04/07/2014


ATTN...WFO...LIX...LCH...

LAT...LON 30499157 29959181 29689265 29669353 29869371 30229350
30649270 30959209 30889174 30499157
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1024. TylerStanfield
1:44 AM GMT on April 07, 2014
Quoting 1011. Grothar:
March 3



April 3




The significant warming trend has paused for now, but in about two weeks, another warming trend should commence.


Westerly trades should prevail once again, according to the CFS, allowing for further warming .
Member Since: June 2, 2013 Posts: 9 Comments: 1402
1023. Patrap
1:43 AM GMT on April 07, 2014
College of DuPage Meteorology
Severe Weather and Flash Flood Warnings
Note: This page will reload every 2 minutes. Warnings are listed with the most recent first.
Click on the station ID to bring up list of recent severe weather statements.
SVR T-STORM WARNING BIRMINGHAM AL - KBMX 842 PM CDT SUN APR 6 2014
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1022. sar2401
1:40 AM GMT on April 07, 2014
Report of hail from the warned thunderstorm in Crenshaw County AL large enough to dent the roof and break the plastic lenses on the light bar on sheriff's department patrol car. Deputy estimated the hail was the size of ping pong balls. Not much for some places but pretty big for us.

Radar dog is starting to pace, first early warning sensor of approaching thunderstorms activated. :-)
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1021. Patrap
1:40 AM GMT on April 07, 2014
Quoting 1018. GeoffreyWPB:


Yeppers.


Lotsa folk in town for it.


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1020. Patrap
1:36 AM GMT on April 07, 2014
Area forecast discussion
National Weather Service New Orleans la
741 PM CDT sun Apr 6 2014

Update...

Zone and coastal packages were updated at 7 PM for issuance of
Tornado Watch 65 until 3 am CDT. Warm front is moving north of the
area at this time. 00z sounding now showing much more unstable
airmass and very little inhibition. Helicity has increased to
476...wet bulb zero down to 10k feet. Convection currently firing
just west and north of the area. All modes of severe weather still
possible. Mesoscale models showing some differences in timing with
the WRF 3km being several hours slower than the hrrr in affecting
the New Orleans area and points east. 35

&&

Previous discussion... /issued 345 PM CDT sun Apr 6 2014/

Synopsis...

In waiting Mode at present. Warm front at 850 mb is well to the
north near Interstate 20. Surface warm front...however...remains
just to the south of Lake Pontchartrain. Temperatures in the
warmer air are in the middle 70s...while north of the front...they
are in the middle 60s. The difference is that in the cooler air...we
have a 3 degree c cap. In the warmer air...the cap is not a
factor. Surface low developing northeast of Houston should
gradually drag warm front north over the next few hours.

Short term...

In the warmer air...factors are in place for severe weather event.
A 75/72 surface ob would produce almost 2300 cape...lifted of
-7...helicity in excess of 300. All modes of severe weather remain
possible...Storm Prediction Center carrying slight risk and hatched 10 percent probability of
strong tornado over our entire County Warning Area. Mesoscale models showing that
main squall line will not cross the area until after midnight. Of
course...there is still potential for discrete supercells in
advance of the line. With most of the heavy rain well to the north
of the area today...heavy rain threat is lower than earlier...but
still exists. Threat now would be from training cells along the
line. Gridded quantitative precipitation forecast will be closer to 2 inches...which is higher
than current wpc quantitative precipitation forecast values. Will maintain Flash Flood Watch for
now with convection yet to arrive.

Categorical probability of precipitation tonight with mention of damaging winds and heavy
rain. Will taper probability of precipitation from the west during the morning on Monday.
Low temperature forecast will be difficult across northern half of
the area tonight...as current temperatures are below overnight low
forecast. Will continue to massage hourly temperature trends
through the late afternoon and early evening. Monday highs will
occur during the afternoon behind the front. Current front is
Pacific in origin and will only bring slightly cooler and drier
air to the area.

Northern stream shortwave will drop into the base of the upper
trough on Tuesday. Much steeper middle level lapse rates will provide
the instability to allow the development of showers and possible
thunderstorms on Tuesday...mainly during the first half of the
day. This will usher in cooler and drier air for the remainder of
Tuesday and Wednesday with temperatures 5 to 10 degrees below
normal. 35
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1019. docrod
1:36 AM GMT on April 07, 2014
Quoting 1014. Patrap:





calling Slim Pickens !!
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1018. GeoffreyWPB
1:35 AM GMT on April 07, 2014
Quoting 1016. Patrap:


Superdome?


Yeppers.
Member Since: September 10, 2007 Posts: 0 Comments: 11538
1017. opal92nwf
1:34 AM GMT on April 07, 2014
Every time there are tornado watches in the FL Panhandle, I will take it seriously when there's a warning, but I don't always hold my breath, as a real significant tornado never seems to materialize here right along the Gulf Coast.

It can happen though, and I am always wary of that.

On March 31, 1962 a tornado roared through Milton Florida killing 17 people, injuring 80, and demolishing 130 homes. The picture above, taken about 30 days after the storm, shows the path of the storm from College Park, (upper right) a subdivision, up the hill across the Hudson family homes (center, see detail below)
(full article here)
Member Since: May 12, 2012 Posts: 11 Comments: 2870
1016. Patrap
1:34 AM GMT on April 07, 2014
Quoting 1012. JRRP:

i´m watching Undertaker vs Brock Lesnar now



Superdome?
Member Since: July 3, 2005 Posts: 428 Comments: 129805
1015. GeoffreyWPB
1:34 AM GMT on April 07, 2014
Quoting 1012. JRRP:

i´m watching Undertaker vs Brock Lesnar now



I'll take Undertaker.
Member Since: September 10, 2007 Posts: 0 Comments: 11538
1014. Patrap
1:34 AM GMT on April 07, 2014



Member Since: July 3, 2005 Posts: 428 Comments: 129805
1013. TropicalAnalystwx13
1:33 AM GMT on April 07, 2014
Quoting 1000. Ameister12:
00z Jackson, MS sounding.

Impressive to say the least.

Beautiful (and dangerous) hodograph.
Member Since: July 6, 2010 Posts: 113 Comments: 32809
1012. JRRP
1:31 AM GMT on April 07, 2014

i´m watching Undertaker vs Brock Lesnar now

Member Since: August 16, 2007 Posts: 0 Comments: 6213
1011. Grothar
1:29 AM GMT on April 07, 2014
March 3



April 3

Member Since: July 17, 2009 Posts: 71 Comments: 27208
1010. sar2401
1:29 AM GMT on April 07, 2014
Quoting Grothar:


I always had fun in my math classes. It was a little rocky at first, but I got used to it.






Chemistry was easy, because we only knew one element.

You were lucky. My hair kept getting caught in my computer.

Member Since: October 2, 2004 Posts: 0 Comments: 17327
1009. beell
1:29 AM GMT on April 07, 2014

01Z Day 1 Probabalistic Tornado

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0805 PM CDT SUN APR 06 2014

VALID 070100Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PART OF THE LOWER MS VALLEY AND CENTRAL GULF COAST STATES...

...LA/MS/AL/WRN FL PANHANDLE...
60-90 METER 500 MB HEIGHT FALLS SPREADING INTO THE LOWER MS VALLEY AND LOW LEVEL WAA WILL CONTINUE TO SUPPORT TSTM DEVELOPMENT THIS EVENING INTO THE OVERNIGHT PERIOD ACROSS THE LOWER MS VALLEY AND CENTRAL GULF COAST STATES...AS A SHORTWAVE TROUGH TRACKS FROM THE SRN PLAINS TO THE OZARKS REGION. THIS WILL SUPPORT AN AREA OF LOW PRESSURE DEEPENING AS IT TRACKS FROM THE UPPER TX COAST TO WRN OR MIDDLE TN BY 12Z MONDAY. 00Z SOUNDINGS INDICATED RELATIVELY SUBSTANTIAL LOW LEVEL MOISTENING HAS OCCURRED FROM LA INTO MS AND AL SINCE 12Z TODAY...WHILE SURFACE OBSERVATIONS SHOWED SURFACE DEWPOINTS IN THE LOWER 70S HAVE MOVED INLAND ACROSS SRN PARTS OF LA. A CONTINUED RETURN OF HIGHER THETAE AIR IS EXPECTED INTO THE LOWER MS VALLEY AND CENTRAL GULF COAST STATES THROUGH THIS FORECAST PERIOD RESULTING IN LOW LCLS. ALTHOUGH INSTABILITY WILL TEND TO REMAIN MARGINAL WITH NWD EXTENT AWAY FROM THE COAST...LOCATIONS WITH SURFACE DEWPOINTS INTO THE MIDDLE 60S COMBINED WITH STRENGTHENING DEEP LAYER WIND FIELD WILL HAVE AN INCREASED TORNADO THREAT AS LOW LEVEL AND DEEP LAYER SHEAR INCREASE. A FEW STRONG TORNADOES WILL BE POSSIBLE THIS EVENING AND OVERNIGHT INTO EARLY MONDAY MORNING ACROSS SERN LA...SRN MS...AND SWRN AL WHERE MOISTENING WILL BE THE GREATEST AND LARGE HODOGRAPH CURVATURE IS EXPECTED AS THE SLY LLJ STRENGTHENS.

...ERN AR/FAR NRN MS INTO WRN TN...
AN INCREASE IN FORCING FOR ASCENT LATE IN THIS FORECAST PERIOD IS EXPECTED ACROSS ERN AR INTO FAR NRN MS AND WRN TN WITHIN THE EXIT REGION OF A STRENGTHENING SSWLY 500 MB JET ACCOMPANYING THE NEWD MOVING SHORTWAVE TROUGH. THIS...COMBINED WITH DPVA...STEEPENING MIDLEVEL LAPSE RATES /7-7.5 C PER KM/...MUCAPE 700-900 J/KG AND RELATIVELY STRONG CLOUD-BEARING SHEAR SUGGEST A FEW STRONGER CORES WILL BE CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL. THIS ACTIVITY WILL BE ELEVATED WITH POINT FORECAST SOUNDINGS SHOWING THE BASES ROOTED BETWEEN 700-850 MB.

...PARTS OF THE NRN/CENTRAL PLAINS TO THE PERMIAN BASIN IN TX... LOSS OF DAY TIME HEATING IS EXPECTED TO SUPPORT AN OVERALL DECREASE IN TSTM POTENTIAL ACROSS THE MIDDLE PART OF THE LOWER 48 STATES. FOR SHORT TERM FORECAST DETAILS FOR THE PERMIAN BASIN WHERE THERE HAVE BEEN A FEW STRONGER STORMS...REFER TO SPC MESOSCALE DISCUSSION #299.

..PETERS.. 04/07/2014
Member Since: September 11, 2007 Posts: 145 Comments: 16920

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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