Middle Atlantic Severe Weather...

By: Zachary Labe , 1:24 AM GMT on May 16, 2009

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"Thoughts on Severe Weather Outbreak of May 15"
Well there is the potential for the first widespread severe weather outbreak of the season in Pennsylvania. Energy is coming together for the best ingredients right over the central Pennsylvania region over the Middle and Lower Susquehanna Valleys. I have never been a fan of early season severe weather outbreaks as they are quite difficult to forecast. In most all May severe weather forecasts there are never quite all the ingredients together and usually the lacking factor in minimal surface instability. This time of year the jet stream is transforming from winter time stratiform events to pure cold front convective events of the summer. During this time period ahead of cold fronts there are many dirty warm fronts that cause debris clouds and inhibit instability. But with extremely strong sunshine this time of year, in cases sensitive like the current one sometimes the clouds will become overcome. If any factor is lacking and busts this event, it will be the lack of sunshine. Looking back on the semi-quiet severe weather season of 2008 there was only one severe weather report in the whole month of May. It occured in Jonestown in Lebanon County with a high wind report with a small bow echo that moved through Lebanon and Dauphin Counties. But typically we get many of these questionable severe weather outbreaks this time of year. MCS activity will be ongoing overnight also and may cause debris clouds over the Middle Atlantic in the morning too. So for this event the potential is there for a supercellular event with a few embedded squall lines capable of damaging winds and a few isolated tornadoes. If clouds end up preventing any instability, the event will cease to exist other than regular thunderstorms. Also there is such high shear values in the lower level of the trophosphere that a few thunderstorms may even be torn apart.

"Current Weather Setup"
Friday night will feature some pretty close temperature/dewpoint contrasts with nearly 95% RH values by 6am Saturday morning. With a slight southeasterly wind and high dewpoints a fog bank has formed over the Atlantic as evident by evening visible satellite. This will track inland across eastern Pennsylvania likely as some low 400ft ceiling stratus clouds. It remains in question how far inland this makes it. Meanwhile a warm front over Virginia will try to lift north bringing a so called dirty warm sector by morning. Once in the warm sector there will be mostly cloudy skies along with periods of light rain showers. Meanwhile to the west an overnight MCS complex currently over Illinois will being move into a more stable environment by morning causing the remnaints to cause clouds out ahead of the remaining showers. But we have hit mid May and the sun is nearly a month from its peak ray value. The sun should be strong enough to devour some of the cloud cover for a partly to mostly cloudy sky cover in the afternoon. As the front approaches an anomalous low level jet will strengthen over Pennsylvania causing impressive kinematics with 0-6km shear values over 45knots. As pockets of instability develop with 500-1000 j/kg CAPE it appears that isolated thunderstorms will begin to form first along natural boundaries such as a sea breeze type boundary over eastern Pennsylvania where a temperature varient of 15degrees will occur and there will be a difference between sun and fog. Those storms though will be weak. Moisture advection with PWATs near 1.75inches will occur over the Susquehanna Valley combining with some sun shine will cause the best ingredients for severe weather as the front nears. By later in the afternoon low level wind veering should allow for supercellular activity to form. These cells ahead of the front will be the ones capable of tornadoes. They are most likely in the Harrisburg-York-Lancaster-Reading Corridor. EHI values will rise to near 2 and helicity is near the highest on the charts. Undirectional shear aloft should help create the natural spin on the atmosphere. Thermodynamics will be lacking though with only LI values near 0 and max CAPE near 1200 j/kg. The SWEAT index is proving impressive though near 250. As the front approaches western Pennsylvania a squall line will develop with a primary threat of wind damage. Freezing levels are high aloft near 1200ft, so the threat of hail will not be widespread. As the front approaches the marine airmass over extreme southeastern Pennsylvania the storms should weaken. QPF totals will likely be near .5inches for many areas with up to 1inch for areas that received the heaviest storms.

"Current Advisories"


"Current Satellite"

(Courtesy of Penn State Meteorology.)

"Current Surface Map and Weekly History of Jet Stream Position"


"Radar for Western Pennsylvania"

"Radar for Central Pennsylvania"

"Radar for Eastern Pennsylvania"


"Forecasts from Storm Prediction Center"
SPC AC 161256

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0756 AM CDT SAT MAY 16 2009

VALID 161300Z - 171200Z


...UPR OH VLY/NY INTO NRN MID ATLANTIC...
LOW LVL MOISTURE WILL CONTINUE TO STREAM NNE INTO PA/NY AHEAD OF
AFOREMENTIONED COLD FRONT AND W OF DIFFUSE WARM FRONT NOW EXTENDING
CNTRL NJ TO CNTRL NY...SUPPORTING MODEST DESTABILIZATION.
INSTABILITY WILL...HOWEVER...REMAIN MARGINAL DUE TO WEAK MID-LVL
LAPSE RATES AND PRESENCE OF VARIABLE CLOUD COVER. AFTN SBCAPE
SHOULD RANGE FROM 500 TO 1000 J/KG IN NY TO NEAR 2000 J/KG IN MD/NRN
VA.

MODERATE WSWLY MID LVL FLOW WILL EXIST OVER THE NERN STATES TODAY
AHEAD OF APPROACHING TROUGH...WITH 500 MB SPEEDS AOA 40 KTS FROM
CNTRL PA NWD INTO NY. PROFILES SHOULD BE FAIRLY
UNIDIRECTIONAL...ALTHOUGH SOME DEGREE OF LOW LVL VEERING WILL EXIST
INVOF WARM FRONT AND PRE-FRONTAL TROUGH OVER ERN PORTIONS OF PA/NY.
TSTMS SHOULD FORM WITH SFC HEATING ALONG AND AHEAD OF COLD FRONT BY
EARLY AFTN. RESIDUAL PRE-FRONTAL STORMS NOW OVER WV MAY STRENGTHEN
BY LATER THIS MORNING...AND OTHER STORMS MAY FORM BY MID AFTN ALONG
LEE TROUGH ACROSS MD/SE PA.

THE PRIMARY THREAT SHOULD BE BOWING SEGMENTS/SMALL LEWPS WITH STRONG
TO DMGG WIND GUSTS. A COUPLE TORNADOES CANNOT BE RULED OUT GIVEN
STRENGTH OF DEEP SHEAR WITH NWD EXTENT...AND GREATER
MOISTURE/LOW-LVL VEERING FARTHER S AND E. OVERALL SEVERE POTENTIAL
SHOULD REMAIN SOMEWHAT LIMITED GIVEN MARGINAL THERMODYNAMIC
ENVIRONMENT...AND SHOULD DIMINISH TOWARD EVENING.

"Tornado Risks"

"Hail Risks"

"Wind Risks"


"Model Analysis"
It has been while since I scrutinized over the models and each variable. But it is beginning to be that time of year. Winter is the most common season for my indepth model analysis, in fact I inspect each run. But in Summer other than severe weather outbreaks I typically just look at the basic 850 heights, 500mb, and 6 hr QPF charts all for the main global models of the GFS and EURO. Anyways as usual there are model discrepancies with the NAM predicting CAPE values much lower than the GFS more in the 500 j/kg range while the GFS is more up to a max of 1400 j/kg. The SREF and MOS guidance though tends to side with the GFS and there are near 1200 j/kg. This indicates that they try to show more sun than the NAM. In any case below are few of my selected maps that detail important indices for thunderstorm development, heavy rainfall potential, and kinematics aloft. Also keep in mind convective temperatures are in the mid 70s to near 80 tomorrow, so they should be reached for cumulus development. I will update these maps throughout the day. Stay tuned!

"15z SREF Model Forecast Lifted Index Values"

(Saturday evening)

"0z NAM Model Forecast SWEAT, Helicity, and CAPE indices"

(Saturday evening)

"0z GFS Model Forecast Precipitable Waters"

(Saturday evening)

"0z GFS Model Forecast EHI Values"

(Saturday evening)

"My Forecast for Severe Weather"
I like the axis for best severe weather to be in central Pennsylvania and up through the Middle and Lower Susquehanna Valleys. These locations will have the highest threat for an isolated tornado. Wind damage though will be common from western Pennsylvania on eastward as the best dynamics are over the state of Pennsylvania. The highest threat for flash flooding will be over eastern Pennsylvania that has recently been rain socked with 2inches just yesterday and flash flood guidance is near 1.5inches in 6hours for flooding to occur. Cold air aloft is lacking for this event with H85s well near 15C, but some intense lightning may still occur especially in the more cellular cells. Impressive high temperatures also may occur depending on much sun there is and I could see highs near Lancaster if the sun comes out potentially up to 87degrees. Dewpoints will be very high also in the 60s for just about the entire state.

"My Severe Weather Risk Map"

(Saturday)
*Note... It has been a while since my severe weather maps have been posted. For review my probability areas are slightly different than the Storm Prediction Center due to the fact of the somewhat rarity of severe weather in Pennsylvania in comparison to other parts of the country. Therefore my moderate risk for Pennsylvania would be similar to a high end SPC slight risk. My 25-50% chance of thunderstorms include 0% chance of severe weather. My 75% chance of thunderstorms include 5% severe weather. My slight risk of severe weather includes 15% severe weather. My moderate risk includes 30% severe weather and my high risk includes 45% chance of severe weather. And after the storm I will plot the storm reports and forecast warnings over my forecast regions for a verification map.

"Conclusions on Severe Weather Outbreak"
So it is another wait and see event in this ever difficult area for forecasting, Pennsylvania. While nothing is never set in stone for the weather, forecasting here in the Appalachians is much more difficult than other parts of the nation. Geographic features play such a large role and then to our east is the Atlantic Ocean. So cloud cover as usual is in the biggest question of concern and I could see how this event easily fizzles out especially if the warm front does not come far enough north and the cloud cover is thicker than expected. Still though thunderstorms should be around the region despite other factors. The low level jet is quite impressive and if we had impressive thermodynamics such as 2000 j/kg CAPE like in late June, this could have been a pretty impressive tornado outbreak. Depending on how the weekend flows, my next weekly forecast blog may be out Sunday evening. Have a wonderful weekend!!! Feel free to add forecast discussions here and storm reports!

Verification Map...


"Storm Reports"


"Here north of Harrisburg 2009 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 2
Severe Thunderstorm Warnings- 1
Tornado Watches- 0
Tornado Warnings- 0
Total Thunderstorms- 4

(Precipitation Stats...)
Flood Watches- 1
Flood Warnings- 0
Monthly Precipitation- 4.30inches
Yearly Precipitation- 11.16inches

(Temperature Stats...)
Heat Advisories- 0
Excessive Heat Warnings- 0
90degree Days- 1
Highest Temperature- 92degrees

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52. Zachary Labe
12:00 AM GMT on May 18, 2009
TheRasberryPatch- I had to cover my plants this evening, dewpoint is 34 here and winds have calmed.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
51. TheRasberryPatch
11:53 PM GMT on May 17, 2009
right now my dewpt is 35F. i guess my soil being too wet and that storm that passed to my west that dropped a little shower yesterday was a blessing that i didn't put my plants in the ground. this cold air would probably kill the plants.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
50. Mason803
11:52 PM GMT on May 17, 2009
Quoting Blizzard92:
Mason803- I know, I tell you what the NWS could care less about its extreme southern counties. They think we are a bunch of hot tropical locales that don't receive any cold weather and or snow.


i agree. everytime we get frost in the growing season i include it on the remarks section of my daily coop report. i can only hope they take note of it.
Member Since: November 5, 2008 Posts: 0 Comments: 1139
49. Zachary Labe
11:41 PM GMT on May 17, 2009
Mason803- I know, I tell you what the NWS could care less about its extreme southern counties. They think we are a bunch of hot tropical locales that don't receive any cold weather and or snow.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
48. Mason803
11:30 PM GMT on May 17, 2009
surprised nws didn't include york and adams county in the frost advisory. kthv and areas similar will have the coldest readings out of the whole region. my dewpoint currently is 29 degrees. didn't get the storms here yesterday. ended up with 0.10" of rain.
Member Since: November 5, 2008 Posts: 0 Comments: 1139
47. Zachary Labe
11:20 PM GMT on May 17, 2009
*New blog coming within the hour for forecasts for all of this week.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
46. TheRasberryPatch
11:16 PM GMT on May 17, 2009
i didn't know they sprayed for them. well, hopefully, the cold air this evening and throughout the night will kill them. they are a menace and want in.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
45. Zachary Labe
10:55 PM GMT on May 17, 2009
Quoting TheRasberryPatch:
did anyone else have an explosion of black flies? they are all over my house and in my garage. I am not sure if they are looking for some warmth or some other reason.

O yes, same here too. I do not think they sprayed for them yet at the Susquehanna River. Once they spray the population begins to dwindle.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
44. TheRasberryPatch
9:02 PM GMT on May 17, 2009
did anyone else have an explosion of black flies? they are all over my house and in my garage. I am not sure if they are looking for some warmth or some other reason.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
43. TheRasberryPatch
3:44 PM GMT on May 17, 2009
tell me about it Blizz. it seemed like throughout the 70's and 80's and 90's we had good April's and wonderful May's. not anymore.

hopefully, next weekend will be bright and sunny and hot.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
42. Zachary Labe
1:41 PM GMT on May 17, 2009
Why can't we ever have a nice Spring? 70s with sunshine and a quick evening thunderstorm.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
41. TheRasberryPatch
11:53 AM GMT on May 17, 2009
i didn't get much from the storms yesterday and last night. 0.17"

i see we have a frost advisory for tomorrow morning. its been a long time since we had temps that cold this late into May.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
40. weathergeek5
2:51 AM GMT on May 17, 2009
it seems like some storms flared up a bit before they approach Delaware.
Member Since: December 25, 2005 Posts: 0 Comments: 1744
39. Zachary Labe
2:13 AM GMT on May 17, 2009
RkTec- Wow, PWATs aloft are several deviations above normal near 2inches, so heavy rain is expected. Flood advisories are out. Thanks for stopping by with your report!!!
Member Since: December 14, 2007 Posts: 284 Comments: 15112
38. RkTec
2:07 AM GMT on May 17, 2009
Just got 0.87 inches of rain in the last half hour.

Some parts of the lehigh valley are reporting in excess of 2 inches of rain within the last hour.
Member Since: January 27, 2009 Posts: 0 Comments: 384
37. Zachary Labe
12:47 AM GMT on May 17, 2009
TheRasberryPatch- Todays storms were ride the ridge top storms. If you note the map I am going to post tomorrow of all the warnings issued over my forecast map, you can see that most of the severe thunderstorms followed right over the main mountain ridges.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
36. TheRasberryPatch
12:44 AM GMT on May 17, 2009
it looks like i might get a bit coming up from Maryland. it also, looks like i have that repel magnet. all last summer the storms passed just to the north of me, like 3 miles if that. and so far today the same thing.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
35. Zachary Labe
12:39 AM GMT on May 17, 2009
TheRasberryPatch- O yes I was nailed, but I was in Carlisle at the time. Everyone says the lightning was vicious here and we even had a rain rate of 7.11inches per hour at the height. .62inches so far today and still raining.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
34. TheRasberryPatch
12:31 AM GMT on May 17, 2009
so far the storms have missed me completely. did the storms hit your house, Blizz? certainly looks like the reds moved to the north of Harrisburg.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
33. Zachary Labe
12:19 AM GMT on May 17, 2009
Snowlover2010- It appears so, unless those cells in N. Maryland can quickly slide NE.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
32. Snowlover2010
12:15 AM GMT on May 17, 2009
so basically i miss out on this one?
Member Since: January 7, 2008 Posts: 2 Comments: 1003
31. Zachary Labe
12:14 AM GMT on May 17, 2009
Snowlover2010- Hey welcome! Severe storms are to your north.


*Unbelievable. As usual I miss every storm. The severe thunderstorm warning was for the center of my house and I was gone near the Carlisle area. Ugh!
Member Since: December 14, 2007 Posts: 284 Comments: 15112
30. Snowlover2010
11:51 PM GMT on May 16, 2009
Hey Bliz! Long time no talk! HeHe. Hey how do u think I am looking as far as severe weather?
Member Since: January 7, 2008 Posts: 2 Comments: 1003
29. TheRasberryPatch
11:46 PM GMT on May 16, 2009
wow, it looks like some big reds just passed to my northwest. i bet Blizz is in the middle of that
Member Since: January 26, 2007 Posts: 72 Comments: 6260
28. TheRasberryPatch
10:54 PM GMT on May 16, 2009
i just saw ch 8 and a full radar of the east coast. this front is strong and impressive. batten down the hatches. haha
Member Since: January 26, 2007 Posts: 72 Comments: 6260
27. Zachary Labe
9:51 PM GMT on May 16, 2009
TheRasberryPatch- The cells in Fulton, Union, and Snyder Counties look severe with wind damage as threat.

TheDawnAwakening- Welcome back! Hope all went well. If anything interesting occurs pictures will be posted.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
26. TheDawnAwakening
9:49 PM GMT on May 16, 2009
Hi Blizzard. I am home from college and my first semester is over. I can see there are some very healthy looking storms to your west and southwest as well as a possible tornadic supercell to your north and northwest. Make sure to take some pictures. It will be a while before we see any severe storm potential for Cape Cod, MA, but thunderstorms are always possible, except this is fog season.
Member Since: October 21, 2008 Posts: 246 Comments: 3970
25. TheRasberryPatch
9:48 PM GMT on May 16, 2009
a thin line coming our way, but like you said looks severe. also, it appears the rain might make it to the Preakness before the race starts.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
24. Zachary Labe
9:30 PM GMT on May 16, 2009
Storms beginning to turn severe...
Member Since: December 14, 2007 Posts: 284 Comments: 15112
23. Zachary Labe
8:48 PM GMT on May 16, 2009
Well cells are lining up to move into the Lower Susquehanna Valley within a few hours. So I guess we will have to wait and see.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
22. TheRasberryPatch
7:24 PM GMT on May 16, 2009
they must have expanded it to include Lebanon

its heating up. i wonder if this severe weather will have any effect on the Preakness
Member Since: January 26, 2007 Posts: 72 Comments: 6260
21. Zachary Labe
6:17 PM GMT on May 16, 2009
TheRasberryPatch- You are in the severe thunderstorm watch... LEBANON. I am building another raised bed box for my vegetable garden expansion this year by the way.


...A TORNADO WARNING REMAINS IN EFFECT UNTIL 215 PM EDT FOR SOUTH
CENTRAL TIOGA COUNTY...
Member Since: December 14, 2007 Posts: 284 Comments: 15112
20. TheRasberryPatch
5:33 PM GMT on May 16, 2009
that storm moved just to the west of me. i was outside and some pretty good cracks of thunder were around. i bet it missed me no more than a mile. i think it must have hit Hershey.
its lightly raining now. the ground is still to wet to plant. i turned the soil one more time and was going to rake it smooth, but the chunks were just too big and wouldn't break apart.

as of now i am not on the watch list. thats fine with me
Member Since: January 26, 2007 Posts: 72 Comments: 6260
19. Zachary Labe
5:19 PM GMT on May 16, 2009
PalmyraPunishment- So you decided to show up? Haha.

Severe Thunderstorm Watch...
Member Since: December 14, 2007 Posts: 284 Comments: 15112
18. upweatherdog
5:02 PM GMT on May 16, 2009
Looking at the mesoanalysis data, the area inside a triangle from State College to Williamsport to Harrisburg and back to State College has best chance for severe thunderstorms this afternoon. The best shear and Helicity seems to be in New York, but shear and helicity is beginning to intensify over central Pennsylvania.
Member Since: October 14, 2007 Posts: 173 Comments: 1372
17. PalmyraPunishment
4:49 PM GMT on May 16, 2009
so uh... looks like we're about to get some interesting weather today into tonight eh? about friggin time.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
16. TheRasberryPatch
4:48 PM GMT on May 16, 2009
i got my plants Blizz. i haven't had a chance so far today. my daughter had soccer this morning. i plan on getting out in a few mins if the pop up storm that just formed to the south of harrisburg doesn't come my way.
Member Since: January 26, 2007 Posts: 72 Comments: 6260
15. weathergeek5
4:40 PM GMT on May 16, 2009
Sun is playing cha cha with the clouds. The clouds are still winning the dance contest.
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14. upweatherdog
4:12 PM GMT on May 16, 2009
Grrrr....It's very windy with snow showers here. It seems like summer-like temps will never come. We get a day of temps in the 60s followed by 3 days in the 30s and 40s with snow showers. Models show warm weather next week, but last week the models showed warm weather this week! It seems like each model run is pushing the warm-up later into May with a stubborn trough trying to punch into the U.P.
Member Since: October 14, 2007 Posts: 173 Comments: 1372
13. Zachary Labe
4:09 PM GMT on May 16, 2009

MESOSCALE DISCUSSION 0845
NWS STORM PREDICTION CENTER NORMAN OK
1105 AM CDT SAT MAY 16 2009

AREAS AFFECTED...PARTS OF WRN/CENTRAL NY...MUCH OF WRN/CENTRAL AND
NERN PA...WV/WRN MD PANHANDLE AND SERN OH

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 161605Z - 161700Z

WW WILL BE POSSIBLE FOR PARTS OF THE DISCUSSION AREA BY EARLY
AFTERNOON.

...WRN/CENTRAL NY INTO CENTRAL PA BY EARLY AFTERNOON...
THREAT FOR SEVERE STORMS IS EXPECTED TO INCREASE BY EARLY AFTERNOON
ACROSS WRN/CENTRAL NY ASSOCIATED WITH A LEAD ONGOING CONVECTIVE
LINE...WHICH AT 1530Z EXTENDED FROM ERN LAKE ONTARIO SSWWD TO NWRN
PA /15 WNW BFD/. AIR MASS IMMEDIATELY EAST OF THIS CONVECTION HAS
BECOME AT LEAST MARGINALLY UNSTABLE...GIVEN SURFACE HEATING WITHIN A
MOIST ENVIRONMENT. 12Z BUF SOUNDING MODIFIED FOR LATEST SURFACE
CONDITIONS IN THIS REGION INDICATE VERY LITTLE CINH AND MLCAPE
VALUES APPROACHING 1000 J/KG. EFFECTIVE BULK SHEAR ACROSS
WRN/CENTRAL NY INTO CENTRAL PA IS ALREADY CONDUCIVE FOR STORM
ORGANIZATION /35-40 KT/. FORCING FOR ASCENT IS SOMEWHAT WEAKER
PRESENTLY WITH THIS LINE OF TSTMS...AS A LEADING IMPULSE LIFTS NEWD
AWAY FROM THIS AREA INTO SRN QUEBEC. HOWEVER...ADDITIONAL SURFACE
HEATING WILL FURTHER DESTABILIZE THE AIR MASS AND SHOULD SUPPORT
GREATER POTENTIAL FOR SUSTAINED UPDRAFTS AND AN ATTENDANT SEVERE
THREAT AS THIS CONVECTIVE LINE PROGRESSES EWD.

...WRN/CENTRAL PA...WV/WRN MD PANHANDLE...WRN/CENTRAL NY...SERN OH
BY MID/LATE AFTERNOON...
MODELS ARE TENDING TO AGREE THAT TSTMS SHOULD INCREASE IN COVERAGE
AND INTENSITY ACROSS WRN PA/NY INTO WV BY MID-LATE AFTERNOON AS THE
COLD FRONT REACHES THIS REGION OF THE UPPER OH VALLEY/LOWER GREAT
LAKES. IN ADDITION...GREATER HEIGHT FALLS/FORCING FOR ASCENT IS
EXPECTED TO REACH THIS REGION BY LATE AFTERNOON COINCIDENT WITH THE
TIMING OF THE COLD FRONT. WITH MODERATE INSTABILITY EXPECTED BY
AFTERNOON COMBINED WITH INCREASING FORCING FOR ASCENT/DEEP LAYER
SHEAR...SEVERE THREAT SHOULD INCREASE ALONG THE COLD FRONT AS WELL.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
12. weathergeek5
3:55 PM GMT on May 16, 2009
Sun is just coming out now
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11. Zachary Labe
3:54 PM GMT on May 16, 2009
weathergeek5- Central Pennsylvania is getting some nice sun, CAPE up to 1500 j/kg near Raystown Lake.

TheRasberryPatch- Yes it is, 84% RH here. The sun should be out more soon within the hour. Did you get any planting done?
Member Since: December 14, 2007 Posts: 284 Comments: 15112
10. TheRasberryPatch
3:47 PM GMT on May 16, 2009
and the atlantic provides moisture also.

it is very humid outside. the sun tried to burn through a couple of times, but the clouds are hanging on for now. temp is 72F with a heat index of 68F
Member Since: January 26, 2007 Posts: 72 Comments: 6260
9. weathergeek5
3:46 PM GMT on May 16, 2009
Quoting Blizzard92:
weathergeek5- Timing will not be the most favorable there, early to mid evening, and you remain under the influence of a marine layer. Still though I would monitor the situation.


The cells could still be strong if they make it this far east. As soon as I posted this comment this shows up:

pecial Weather Statement

Statement as of 11:16 AM EDT on May 16, 2009

The Storm Prediction Center in Norman Oklahoma has placed all of
southeast PA and the northern counties on the Delmarva under a
slight risk for severe thunderstorms this afternoon. Storms may
contain very strong winds and frequent cloud to ground lightning
strikes.

If you see or hear lightning or thunder please go indoors
immediately and remain there until the storms have passed.

Monitor NOAA Weather Radio for the latest information... forecasts... and
warnings.


Member Since: December 25, 2005 Posts: 0 Comments: 1744
8. Zachary Labe
3:12 PM GMT on May 16, 2009
upweatherdog- We also get some additional moisture aided from the Chesapeake to our south.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
7. upweatherdog
3:02 PM GMT on May 16, 2009
Quoting Blizzard92:
Very high dewpoint here, 68degrees, highest of entire year. 71degree air temperature with mostly cloudy skies.


My area has never had a dewpoint reach 60F without precipitation.lol

That just shows how hard it is for gulf moisture to make it this far north!
Member Since: October 14, 2007 Posts: 173 Comments: 1372
6. Zachary Labe
3:00 PM GMT on May 16, 2009
weathergeek5- Timing will not be the most favorable there, early to mid evening, and you remain under the influence of a marine layer. Still though I would monitor the situation.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
5. weathergeek5
2:54 PM GMT on May 16, 2009
We had some dense fog here; it has burned off but it is remaining cloudy. SPC took me out of the slight risk.
Member Since: December 25, 2005 Posts: 0 Comments: 1744
4. Zachary Labe
2:29 PM GMT on May 16, 2009
Very high dewpoint here, 68degrees, highest of entire year. 71degree air temperature with mostly cloudy skies.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
3. Zachary Labe
1:20 PM GMT on May 16, 2009
upweatherdog- Thanks! I am hoping to do some planting this weekend if there isn't too much rain.

seflagamma- Thanks for stopping by! Have a wonderful weekend.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
2. seflagamma
1:19 PM GMT on May 16, 2009
Hi Bliz,

You have some nice plants growing in your garden I see! I know you all up north were so ready to get out in the yard again!

You have a wonderful weekend!!!

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About Blizzard92

Cornell University- Atmospheric Sciences Undergrad; Research Assist.- Onset of Spring Indices Toolbox; Interests- Small spatial scale climatolology

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Linglestown, PA
Elevation: 520 ft
Temperature: 24.2 °F
Dew Point: 15.2 °F
Humidity: 68%
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Wind Gust: 9.0 mph
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