June 27 Severe Weather...
"Thoughts on Severe Weather Outbreak of June 27"
Well we have another day of severe weather on our hands. For yesterday it was very quiet most of the day. It started off very cloud with some drizzle around especially in southern sections. In fact Johnstown and Bradford had low cloud ceilings around 1000ft until around noon. After noon the sun broke out fully in most areas and temperatures soared into the upper 80s with dewpoints in the mid 60s in most locations. Atmospheric soundings were not too impressive for most of the day with some slight CIN over southeastern sections and modest CAPE in most areas. PWATS though were near an impressive 2inches so there was a definite high moisture content aloft. Later in the day a shortwave enhanced thunderstorms over Ohio. They quickly became severe. Due to low winds aloft they moved at a slow pace and a training thunderstorm event occured with some flooding in Ohio. The thunderstorms also became severe with many reports of wind damage. The thunderstorms then moved into western Pennsylvania as instibility had become much higher with CAPE around 3000 j/kg in western Pennsylvania. By evening the thunderstorms formed a small line in the form of a weak bow echo causing some wind damage in many locations. Johnstown, Pennsylvania recorded a 70mph wind gust. Pittsburgh reported lots of damage in the metro area and Erie reported nickel sized hail near the metro along with some trees down. The line continued to move across central Pennsylvania before weakening near Harrisburg. I received a light thunderstorm with .02inches of rain. Overall yesterday my forecast was pretty spot on with a slight risk. I guess I could have not put a slight risk for southeastern Pennsylvania, but o well you cannot be perfect. Here is my verification map...

"Current Weather Setup"
Pretty simple severe weather setup today. This morning there are some left over sprinkles from last nights thunderstorm complexes which was focused along an outflow boundary. Clouds are scattered about the region thicker in some spots than others. But from what I can tell when looking at the current satellite is that the clouds are thinning out and moving out of the state. Currently near Pittsburgh a MCV is moving through relatively slowly. This feature will continue to move east throughout the day. As hot and humid air develops east of the Appalachians, the MCV will provide a trigger for thunderstorms to develop. Steep lapse rates, low LI index, and high CAPE values near 3000 j/kg will lead to the development of severe thunderstorms. Winds aloft are relatively light though which will make an organized widespread wind damage outbreak hard to come by. But with weak winds aloft and PWATs near 2inches heavy rain and flash flooding may be a threat. Currently dewpoints statewide are around the mid 60s with temperatures already nearing 80degrees in the south. Todays event will be very similiar to what has been happening in northwest Ohio the last couple of days. Stay tuned for more updates throughout the day as the latest soundings come in around 12z.
"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"
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0101 AM CDT FRI JUN 27 2008
...N-CENTRAL APPALACHIANS TO MID-ATLANTIC COAST...
TIMING OF LARGE SCALE ASCENT ASSOCIATED WITH MCV...FAVORABLE LOW
LEVEL MOISTURE...AND STRONGEST PORTION OF DIURNAL HEATING CYCLE FOR
WEAK CINH...FAVORS POTENTIAL FOR RELATIVE CONCENTRATION OF STG-SVR
CONVECTION OVER THIS AREA THIS AFTERNOON. MAIN CONCERN WILL BE
DAMAGING GUSTS...WITH ISOLATED SVR HAIL ALSO POSSIBLE. GIVEN
WEAKNESS OF AMBIENT FLOW -- E.G. 20 KT OR LESS BELOW 600 MB IN MOST
AREAS -- MAJOR WIND DAMAGE EVENT APPEARS LESS PROBABLE THAN
AGGREGATION OF MORE LOCALIZED DAMAGING GUST EVENTS. SFC DEWPOINTS
MID 60S TO LOW 70S F OVER LOWER ELEVATIONS WILL CONTRIBUTE TO
MLCAPES UP TO 2500 J/KG...WITH NEARLY UNIDIRECTIONAL
DEEP-TROPOSPHERIC PROFILES SUPPORTING LINEAR/FORWARD-PROPAGATING
CONVECTIVE STRUCTURES.
"Tornado Risks"
"Hail Risks"
"Wind Risks"

"Model Analysis"
The models are in pretty similar agreement to today's forecast. Below is the NAM and SREF models with forecast CAPE, SWEAT, and Helicity. The NMM model seemed to have an initiation problem so I could not post it below. CAPE values look like they will get up to 3000 j/kg in southeastern Pennsylvania. The LI index should remain low and very supportive of the development of strong to severe convection. Shear values are pretty low today with little to no helicity so tornadoes should not be too much of a threat today. The largest threats today are for heavy rain and strong winds. Also the atmosphere is containing some high energy levels today so lightning could be quite intense with some of the storms that form. One inhibiting factor today could be these morning clouds that are around. If they do not dissapate soon then we could have some problems for convection trying to form. Stay tuned for more updates throughout the day.
"3z SREF Model Forecast Max Cape Index"

(Friday afternoon)
"12z NAM Model Forecast SWEAT, Helicity, and CAPE indices"

(Friday afternoon)
"My Forecast for Severe Weather"
Below is my severe weather map for today and I am looking at a slight risk over eastern Pennsylvania and a isolated chance of western Pennsylvania. The MCV will spark thunderstorms beginning in westcentral Pennsylvania. As they move east they will tap into the warm, moist air in eastern Pennsylvania and become severe most likely. Still a chance exists across western Pennsylvania for an orographic pulse thunderstorm to develop and become severe. The Storm Prediction Center in Norman, Oklahoma is in similiar correspondance with their forecast to mine. For Saturday another severe weather map will be issued around early Saturday morning. Also as usuall a verification map on today's severe weather will be issued tomorrow.
"My Severe Weather Risk Map"

(Friday)
"Conclusions on Severe Weather Outbreak"
For Saturday an approaching front will be headed in the northeast's direction. Saturday high temperatures will soar to 90degrees in southern Pennsylvania. Elsewhere temperatures will be in the mid to upper 80s. Dewpoints across the state should be in the upper 60s to low 70s. It is too far out too see if clouds will inhibit severe thunderstorms, but at this point I would say ample sunshine should be available. The strong cold front is ahead of another upper level trough that will drop temperatures back to seasonal values along with drier air. CAPE values for Saturday are near 3500 j/kg according to the NAM. The GFS is still high though around 3000 j/kg. Looking at any CAP to the environment and there is no CAP that should preclude any convective development. Also the SREF model shows 2000 j/kg over southern Pennsylvania for Saturday. Timing with the front is uncertain at this point, but the closer the front the higher the shear and helicity values are. The uncertainty of the fronts timing kept severe weather chances in for Saturday and Sunday. Also some models show slowing of the front around central Pennsylvania. Sunday looks to be the main show here in central and eastern Pennsylvania, dynamics will be similar to what western Pennsylvania delt with Saturday. Though I am worried about debris cloud from the day before inhibiting severe thunderstorm development. That factor definitely needs to be monitored. All in all it looks like a pretty hefty widespread severe weather outbreak will be headed towards Pennsylvania. More updates will be coming with a new blog each day for Saturday and Sunday highlighting each day's severe weather threat. Have a wonderful Friday!!!
"Storm Reports"

"Here north of Harrisburg 2008 statistics"
(Severe Weather Stats...)
Severe Thunderstorm Watches- 3
Severe Thunderstorm Warnings- 1
Tornado Watches- 1
Tornado Warnings- 0
Total Thunderstorms- 15
(Precipitation Stats...)
Flood Watches- 4
Flood Warnings- 3
Monthly Precipitation- 3.53inches
Yearly Precipitation- 21.60inches
(Temperature Stats...)
Heat Advisories- 4
Excessive Heat Warnings- 0
90degree days- 5
Reader Comments
Page: 1 — Blog Index
Heavy rainers are always fun.
any forecasts for next week for the mid atlantic?
my lettuce is really taken off, especially the buttercrunch. we need more hot weather for the tomatoes to turn and for my pool of course.
We did have an overnight shower, enough to make the roads wet, but not enough to register in my rain gauge.
JDinWPA- You have had alot of severe thunderstorms out your way this year.
MESOSCALE DISCUSSION 1588
NWS STORM PREDICTION CENTER NORMAN OK
1037 AM CDT FRI JUN 27 2008
AREAS AFFECTED...MID-ATLC REGION
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 271537Z - 271800Z
VSBL SATL SHOWS A WEAK MCV OVER SW PA THAT WILL TRACK EWD INTO ERN
PA BY MID-AFTN. VWP AT CHARLESTON WV HAS CAPTURED A MODEST BELT OF
MID-LEVEL FLOW WRAPPING ALONG THE SRN FRINGE OF THIS FEATURE WITH
AROUND 30 KTS NOTED. THIS JET WILL LIKELY TRANSLATE ACROSS
NRN/CNTRL VA INTO MD...DE...NJ AND PARTS OF SE PA THROUGH THE AFTN.
CLEAR SKIES E OF THE BLUE RIDGE AND FM SE PA/NJ SWD HAVE CONTRIBUTED
TO RAPIDLY DESTABILIZING CONDITIONS AS TEMPERATURES HAVE SOARED
THROUGH THE 80S WHILE MAINTAINING UPR 60S TO NEAR 70F SFC DEW
POINTS. TSTMS SHOULD READILY FORM/INTENSIFY ALONG ERN EDGE OF THE
HIGHER CLOUDS ALONG THE CNTRL APLCNS THROUGH THE AFTN...AND GROW
STRONGER AS THEY ENCOUNTER THE STRONG INSTABILITY AXIS FARTHER TO
THE EAST.
ALTHOUGH DEEP LAYER SHEAR AND MID-LEVEL LAPSE RATES WILL BE
WEAK...LOW-LEVEL LAPSE RATES WILL BE STEEP. AS MULTICELL STORMS
CONGEAL...LARGELY UNIDIRECTIONAL FLOW REGIME THROUGH THE COLUMN
/ENHANCED BY THE 30 KT WLY FLOW/ WILL RESULT IN LOOSELY ORGANIZED
LINE SEGMENTS CAPABLE OF PRODUCING DMGG WINDS AND PERHAPS SMALL
HAIL. ACTIVITY SHOULD PROGRESS TOWARD THE MID-ATLC COAST LATER THIS
AFTN.
A WW WILL BE POSSIBLE FOR PARTS OF THIS REGION.
Tornadoes
Probability of 2 or more tornadoes
Low (10%)
Probability of 1 or more strong (F2-F5) tornadoes
Low (<2%)
Wind
Probability of 10 or more severe wind events
Mod (50%)
Probability of 1 or more wind events > 65 knots
Low (20%)
Hail
Probability of 10 or more severe hail events
Mod (30%)
Probability of 1 or more hailstones > 2 inches
Low (20%)
Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
High (70%)
NATIONAL WEATHER SERVICE STATE COLLEGE PA
158 PM EDT FRI JUN 27 2008
PAZ026-027-034>036-271845-
BEDFORD-FRANKLIN-FULTON-HUNTINGDON-MIFFLIN-
158 PM EDT FRI JUN 27 2008
...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL FRANKLIN...
NORTHEASTERN BEDFORD...NORTHEASTERN FULTON...SOUTHERN HUNTINGDON AND
SOUTHWESTERN MIFFLIN COUNTIES...
AT 154 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE TRACKING
A STRONG THUNDERSTORM LOCATED NEAR BROAD TOP CITY...MOVING EAST AT 27
MPH.
WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.
VERY HEAVY RAIN WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO
POND ON ROADS AND QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS.
THIS STORM WILL BE NEAR WATERFALL AROUND 205 PM...SALTILLO AROUND 210
PM...THREE SPRINGS AROUND 215 PM...ORBISONIA AROUND 225 PM...SHADE
GAP AROUND 230 PM AND NEWTON HAMILTON AROUND 235 PM.
THIS WILL IMPACT THE FOLLOWING CENTRAL PENNSYLVANIA INTERSTATES...THE
PENNSYLVANIA TURNPIKE BETWEEN MILE MARKERS 190 AND 196.
THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 522.
NATIONAL WEATHER SERVICE STATE COLLEGE PA
215 PM EDT FRI JUN 27 2008
PAZ004>006-271900-
MCKEAN-POTTER-WARREN-
215 PM EDT FRI JUN 27 2008
...STRONG THUNDERSTORMS WILL AFFECT EAST CENTRAL WARREN...MCKEAN AND
NORTHWESTERN POTTER COUNTIES...
AT 211 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM OLEAN TO
KINZUA DAM...MOVING EAST AT 21 MPH.
WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THESE STORMS.
VERY HEAVY RAIN WILL FALL FROM THESE STORMS...AND WILL CAUSE WATER TO
POND ON ROADS AND QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS.
THESE STORMS WILL BE NEAR MARSHBURG AROUND 235 PM...LEWIS RUN AROUND
240 PM...WESTLINE AROUND 250 PM AND CYCLONE AROUND 300 PM.
THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 6...ROUTE
219...STATE ROAD 46...STATE ROAD 59...STATE ROAD 446.
NYC007-107-PAC015-115-272045-
/O.NEW.KBGM.SV.W.0152.080627T1947Z-080627T2045Z/
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BINGHAMTON NY
347 PM EDT FRI JUN 27 2008
THE NATIONAL WEATHER SERVICE IN BINGHAMTON HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
SOUTHWESTERN BROOME COUNTY IN CENTRAL NEW YORK...
SOUTHERN TIOGA COUNTY IN CENTRAL NEW YORK...
NORTHEASTERN BRADFORD COUNTY IN NORTHEAST PENNSYLVANIA...
NORTHWESTERN SUSQUEHANNA COUNTY IN NORTHEAST PENNSYLVANIA...
* UNTIL 445 PM EDT
* AT 346 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
BARTON...MOVING EAST AT 20 MPH.
* THE SEVERE THUNDERSTORM WILL BE NEAR...
NICHOLS BY 400 PM EDT...
LOUNSBERRY AND TIOGA CENTER BY 405 PM EDT...
OWEGO AND WINDHAM BY 415 PM EDT...
APALACHIN BY 430 PM EDT...
TIOGA TERRACE AND WEST CORNERS BY 440 PM EDT...
VESTAL AND VESTAL CENTER BY 445 PM EDT...
A SEVERE THUNDERSTORM WARNING MEANS THAT SEVERE WEATHER IS OCCURRING
OR IS IMMINENT. WIND GUSTS IN EXCESS OF 60 MPH...HAIL THREE-QUARTERS
OF AN INCH IN DIAMETER OR LARGER...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL LIKELY. IF YOU ARE IN THE PATH OF THIS SEVERE STORM
MOVE TO SAFE SHELTER NOW.
PLEASE REPORT HAIL...OR DAMAGING WINDS TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE AT 1-877-633-6772...OR BY EMAIL AT
BGM.STORMREPORT@NOAA.GOV.
LAT...LON 4216 7585 4190 7591 4201 7656 4215 7653
4216 7653 4219 7653
TIME...MOT...LOC 1947Z 278DEG 18KT 4209 7646
PAC015-115-272115-
/O.NEW.KBGM.SV.W.0153.080627T2011Z-080627T2115Z/
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BINGHAMTON NY
411 PM EDT FRI JUN 27 2008
THE NATIONAL WEATHER SERVICE IN BINGHAMTON HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
NORTHEASTERN BRADFORD COUNTY IN NORTHEAST PENNSYLVANIA...
SUSQUEHANNA COUNTY IN NORTHEAST PENNSYLVANIA...
* UNTIL 515 PM EDT
* AT 407 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
WINDHAM...MOVING SOUTHEAST AT 20 MPH.
* THE SEVERE THUNDERSTORM WILL BE NEAR...
ROME BY 420 PM EDT...
WARREN CENTER BY 430 PM EDT...
WARREN CENTER AND HERRICKVILLE BY 435 PM EDT...
LE RAYSVILLE BY 440 PM EDT...
BRUSHVILLE AND FRIENDSVILLE BY 445 PM EDT...
RUSHVILLE BY 450 PM EDT...
A SEVERE THUNDERSTORM WARNING MEANS THAT SEVERE WEATHER IS OCCURRING
OR IS IMMINENT. WIND GUSTS IN EXCESS OF 60 MPH...HAIL THREE-QUARTERS
OF AN INCH IN DIAMETER OR LARGER...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL LIKELY. IF YOU ARE IN THE PATH OF THIS SEVERE STORM
MOVE TO SAFE SHELTER NOW.
PLEASE REPORT HAIL...OR DAMAGING WINDS TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE AT 1-877-633-6772...OR BY EMAIL AT
BGM.STORMREPORT@NOAA.GOV.
LAT...LON 4192 7648 4201 7636 4200 7633 4200 7619
4182 7576 4164 7596 4164 7599
TIME...MOT...LOC 2011Z 306DEG 19KT 4196 7633
MESOSCALE DISCUSSION 1597
NWS STORM PREDICTION CENTER NORMAN OK
0346 PM CDT FRI JUN 27 2008
AREAS AFFECTED...PORTIONS OF THE NORTHEAST
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 272046Z - 272145Z
ISOLATED SEVERE STORMS WILL CONTINUE TO DEVELOP ACROSS PORTIONS OF
THE NORTHEAST OVER THE NEXT FEW HOURS. COVERAGE AND INTENSITY IS
EXPECTED TO DECREASE AFTER SUNSET AT INSTABILITY WANES.
NUMEROUS PULSE TYPE THUNDERSTORMS HAVE DEVELOPED ACROSS PORTIONS OF
THE NORTHEAST THIS AFTERNOON IN ASSOCIATION WITH A WEAK SURFACE
TROUGH AND AN UPPER LEVEL WAVE NOTED ON WV IMAGERY INVOF ERN NY AND
VT. MOIST AND UNSTABLE AIRMASS CONTINUES AHEAD OF ONGOING
CONVECTION...AND GIVEN SLIGHT COOLING IN ASSOCIATION WITH MID LEVEL
WAVE STORMS WILL CONTINUE TO DEVELOP OVER THE NEXT FEW HOURS DESPITE
SLOWLY COOLING SURFACE TEMPERATURES. STRONGEST FLOW REMAINS AHEAD OF
CURRENT CONVECTION...ESP OVER PORTIONS OF NEW ENGLAND. THIS WILL
SUPPORT HAIL UP TO ONE INCH AND DMGG WIND GUSTS IN STRONGER
UPDRAFTS. AS STORMS MOVE OVER THE COASTAL WATERS...MARINE HAZARDS
EXIST AS WELL. STORMS WILL GRADUALLY DECREASE IN BOTH COVERAGE AND
INTENSITY AS RADIATIONAL COOLING CREATES A MORE STABLE AIRMASS.
PAC015-115-131-272200-
/O.NEW.KBGM.SV.W.0155.080627T2112Z-080627T2200Z/
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BINGHAMTON NY
512 PM EDT FRI JUN 27 2008
THE NATIONAL WEATHER SERVICE IN BINGHAMTON HAS ISSUED A
* SEVERE THUNDERSTORM WARNING FOR...
EASTERN BRADFORD COUNTY IN NORTHEAST PENNSYLVANIA...
SOUTHWESTERN SUSQUEHANNA COUNTY IN NORTHEAST PENNSYLVANIA...
NORTHERN WYOMING COUNTY IN NORTHEAST PENNSYLVANIA...
* UNTIL 600 PM EDT
* AT 511 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
WYSOX...MOVING EAST AT 30 MPH.
* THE SEVERE THUNDERSTORM WILL BE NEAR...
CAMPTOWN AND WYALUSING BY 520 PM EDT...
SPRING HILL BY 525 PM EDT...
LACEYVILLE BY 530 PM EDT...
RUSH BY 535 PM EDT...
AUBURN CENTER AND MESHOPPEN BY 540 PM EDT...
SPRINGVILLE AND LAKE CAREY BY 550 PM EDT...
A SEVERE THUNDERSTORM WARNING MEANS THAT SEVERE WEATHER IS OCCURRING
OR IS IMMINENT. WIND GUSTS IN EXCESS OF 60 MPH...HAIL THREE-QUARTERS
OF AN INCH IN DIAMETER OR LARGER...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL LIKELY. IF YOU ARE IN THE PATH OF THIS SEVERE STORM
MOVE TO SAFE SHELTER NOW.
PLEASE REPORT HAIL...OR DAMAGING WINDS TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE AT 1-877-633-6772...OR BY EMAIL AT
BGM.STORMREPORT@NOAA.GOV.
LAT...LON 4176 7575 4152 7584 4168 7647 4186 7641
TIME...MOT...LOC 2112Z 283DEG 29KT 4175 7632
Sorry to interupt the serious discussion of Now's Weather. I'll be looking forward to your update on severe potential for Sat and Sun. Suppose you will wait for the 8pm models.
It was reported by a citizen and was announced over my fire pager.
MDFirefighter- Wow, hopefully there was no serious damage or injuries. Thanks for posting that.
cchamp6- A cell just to my west blew a roof off someones home and there was no warning on the cell and not even a special weather statement.
thanks for considering my request. : ))
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