National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 210355
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1155 PM EDT MON MAY 20 2013

.SYNOPSIS...
A WARM HUMID AIRMASS WILL REMAIN IN PLACE THROUGH MID WEEK.
EXPECT WELL ABOVE NORMAL AFTERNOON TEMPERATURES THROUGH WEDNESDAY
BEFORE A COLD FRONT BRINGS TEMPERATURES BACK BELOW NORMAL WITH
DRIER CONDITIONS FOR THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
THE REGION IS UNDER A WARM AND HUMID AIRMASS SO IT WILL BE A
MUGGY OVERNIGHT. AREAS OF LOW CLOUDS AND PATCHY FOG ARE POSSIBLE
LATE TONIGHT SINCE WILL DEWPOINTS REMAIN HIGH AND WINDS WILL FALL
OFF TO LIGHT AND VARIABLE. CONVECTION OVER LAKE HURON AND SOUTHERN
MICHIGAN CRESTING THE UPPER RIDGE TO OUR WEST COULD SNEAK INTO THE
NW AFTER MIDNIGHT...BUT AT THIS TIME SHORT RANGE HIGH RES MODELS
ARE FORECASTING IT TO DIMINISH RAPIDLY BEFORE IT BECOMES A
PROBLEM. WILL HAVE TO BE WATCHED BUT FOR NOW I JUST HAVE SMALL
CHANCES FOR THUNDERSTORMS OVER NWRN AREAS LATER TONIGHT. MINS WILL
AGAIN BE MUGGY UPPER 50S AND LOWER 60S.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
TUESDAY...WE WILL BE BE WELL INTO THE WARM SECTOR AHEAD OF THE STORM
CRAWLING IN FROM THE NORTHERN PLAINS/MIDWEST/UPPER LAKES. THE WARM
SECTOR AIR WILL BE QUITE WARM FOR THIS TIME OF YEAR...HAVING SPENT
PLENTY OF TIME COOKING OVER THE MS AND OH VALLEYS WITH GOOD GULF
INFLOW. TEMPS THERE RIGHT NOW ARE ABOUT 10F ABOVE AVERAGES.
THEREFORE...SUMMERTIME TEMPS OF UPPER 70S IN THE HILLS TO MID 80S IN
THE VALLEYS ARE EXPECTED ON TUESDAY. ALONG WITH THE WARM
TEMPERATURES...THE DEWPOINTS WILL BE SOLIDLY IN THE 60S. THIS
WARM...MOIST AIR AND A WEAKENING RIDGE MOVING OVERHEAD AND A LITTLE
TO OUR EAST WILL CREATE A GOOD SITUATION FOR SCT AFTN CONVECTION.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
THE LARGE UPPER LEVEL LOW BRINGING SEVERE WEATHER THROUGHOUT THE
MIDWEST WILL SLOWLY MAKE ITS WAY EASTWARD. THIS FLOW SHOULD BRING A
RATHER UNSETTLED PERIOD THROUGH THE WORK WEEK. AS THE UPPER LEVEL
RIDGE CONTINUES TO BREAK DOWN...STORMS WILL SLOWLY APPROACH.  SEVERE
OUTLOOK FOR DAY3/WED HAS THE WESTERN HALF OF THE CWA IN THE SLIGHT
RISK. SOUTHEASTERLY MOISTURE...COUPLED WITH INSTABILITY FROM THE
FRONT AND DAYTIME HIGHS IN THE 80S SHOULD ALLOW FOR A SUFFICIENT
ENVIRONMENT FOR DAYTIME STORMS/SHOWERS. SHEAR SHOULD BE
DECENT...ESPECIALLY AS MID RANGE MODELS ARE HINTING AT A LLJ THROUGH
WEDNESDAY AFTERNOON. THURSDAY WILL AGAIN FEATURE SCT/NMRS TSRA. THE
MED RANGE GUID IS NOW PRETTY SOLID WITH A THURS NIGHT/EARLY FRIDAY
PASSAGE OF THE COLD FRONT ASSOCD WITH THE SYNOPTIC SCALE STORM. MUCH
COOLER AIR AND DRIER CONDITIONS SHOULD FOLLOW FOR THE WEEKEND. ECMWF
HAS BACKED OFF ON THE COLD-NESS OF THE AIR MOVING DOWN WITH THE BIG
1030MB HIGH FOR THE WEEKEND...THOUGH IT LOOKS LIKE THE ZERO C LINE
AT 8H COULD CLIP THE NORTHWESTERN CORNER OF PA. MIN TEMPS FOR
SATURDAY MORNING WILL BE COOL BUT HAVE KEPT THEM IN THE LOW 40S TO
UPPER 30S. DRIER AIR ASSOCIATED WITH THIS FRONT SHOULD KEEP
PRECIPITATION OUT OF THE FORECAST THROUGH THE WEEKEND...WITH WEAK
HIGH PRESSURE BUILDING THROUGH SUNDAY. MEMORIAL DAY MAY SEEM SOME
CLOUDINESS AS THE RIDGE BREAKS DOWN TO DUE NORTHWESTERLY FLOW.
MOISTURE FROM A WEAK SHORTWAVE COULD BRING PRECIPITATION ALONG THE
MASON DIXON MONDAY EVENING...YET DUE TO IT BEING ON THE EDGE OF THE
FORECAST MUCH COULD CHANGE.

&&

.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
THE MAIN AVIATION CONCERN OVERNIGHT IS THE POTENTIAL OF FOG. HIGH
DEWPOINTS AND LIGHT WINDS WILL LEAD TO AREAS OF FOG...MAINLY AFTER
06Z. BULK OF MDL GUIDANCE CONTINUES TO TARGET THE EASTERN THIRD OF
THE STATE FOR THE LOWEST VSBYS DUE TO A NEARLY CALM WIND AND LOWER
DWPT DEPRESSIONS IN THIS AREA. THE COMBINATION OF MDL DATA AND 03Z
SFC DWPT DEPRESSIONS SUGGEST KLNS AND KMDT ARE VERY LIKELY TO
EXPERIENCE A PERIOD OF IFR VSBYS LATE TONIGHT. KAOO ALSO APPEARS
LIKELY TO EXPERIENCE A PERIOD OF IFR VSBYS...DUE IN PART TO WET
GROUND FROM A LATE DAY SHRA. ELSEWHERE...THE FOG THREAT NOT QUITE
AS GREAT. HOWEVER...A BRIEF PERIOD OF LOW VSBYS IS POSSIBLE JUST
BEFORE DAWN.

AM FOG SHOULD BURN OFF BY ARND 13Z TUESDAY. AFTER THAT...THERE IS
A HIGH DEGREE OF CONFIDENCE IN WIDESPREAD VFR CONDS FROM LATE AM
THRU TUE EVENING. HOWEVER...SCT PM TSRA WILL AGAIN BE AN AVIATION
CONCERN. THE BEST CHC OF AN AFTN TSRA AND ACCOMPANYING BRIEF VSBY
REDUCTION WILL BE ACROSS THE N MTNS AND SOUTHWARD ALONG THE LAUREL
HIGHLANDS. HOWEVER...LATEST MDL DATA INDICATES SOME POSSIBILITY OF
A LINE OF TSRA SWEEPING SE ACROSS THE ENTIRE REGION TUE EVENING.

.OUTLOOK...
WED-THU...SCT THUNDERSTORM IMPACTS POSSIBLE...MAINLY IN THE PM.
FRI-SAT...NO SIG WX EXPECTED.
-- End Changed Discussion --

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...LA CORTE/CERU
AVIATION...FITZGERALD