-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 201322
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
912 AM EDT MON MAY 20 2013

.SYNOPSIS...
A WARM FRONT WILL ATTEMPT TO MOVE THROUGH THE AREA TODAY. IT SHOULD
SUCCEED IN DOING SO...BRINGING INCREASING WARMTH AND HUMIDITY TO
THE REGION THROUGH MID-WEEK. EXPECT WELL ABOVE NORMAL AFTERNOON
TEMPERATURES TUESDAY AND WEDNESDAY. TEMPERATURES WILL COOL BACK
BELOW NORMAL WITH DRIER CONDITIONS BY THE WEEKEND AS A VERY COLD
AIRMASS DROPS OUT OF CENTRAL CANADA INTO THE GREAT LAKES AND
NORTHEASTERN UNITED STATES.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
MOISTURE AND ASSOCIATED EXTENSIVE LOW STRATUS/FOG...STILL TRAPPED
UNDER THE STEEP INVERSION WILL GRADUALLY BE MIXED OUT/DISSIPATED
FROM WEST TO EAST DURING THE DAY TODAY THANKS TO A MEAN SFC-850 MB
FLOW FROM THE SSW.

THE STRATUS WILL BE MOST STUBBORN TO BREAK UP ACROSS THE EASTERN
HALF OF THE CWA...WHERE SOME AREAS MAY NOT GET RID OF THE CLOUDS BY
THE END OF THE DAY. THE FRONT IS STILL VERY DIFFICULT TO MAKE OUT
DUE TO RATHER SIMILAR DEWPOINTS AND RATHER GENTLE GRADIENT TO THE
SFC PRESSURE. THE RIDGE AXIS IS WELL OFF SHORE NOW BUT THE LACK OF
GOOD SRLY WIND IS A TICK MARK ON THE NEGATIVE SIDE FOR THE FRONT TO
MAKE IT THROUGH THE AREA TODAY. ON THE PLUS SIDE IF THE LEDGER SHEET
- THE STRONG MAY SUNSHINE - WE ARE NOW ONLY 1 MONTH FROM SOLSTICE -
SHOULD WORK ON THE EDGES OF THE STRATUS AND PERCOLATE SOME DIURNAL
CU. ALL MDL SOUNDINGS BREAK THE INVERSION AND CREATE ISOLD/SCT SHRA
IN THE SRN TIER AND ANOTHER AREA OVER THE NWRN MTS. WILL KEEP POPS
LOWEST IN THE NE AND CENTRAL MTS.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MORE STRATUS AND FOG ARE POSSIBLE TONIGHT SINCE DEWPOINTS REMAIN
HIGH AND WINDS WILL STILL BE LIGHT. WILL COUNT ON THE LACK OF SUN
TO KILL THE SHOWERS/STORMS THIS EVENING...AND LEAVE POPS LESS THAN
20 PCT FOR THE BULK OF THE NIGHT. CONVECTION CRESTING THE UPPER
RIDGE TO OUR WEST COULD SNEAK INTO THE NW BY MORNING...BUT THIS IS
JUST WORTH A LOW CHC POP AT THIS POINT. MINS WILL AGAIN BE MUGGY
UPPER 50S AND LOWER 60S.

ON TUESDAY...WE SHOULD 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 SUNDAY/...
-- Changed Discussion --
THE MEDIUM RANGE GUIDANCE CONTINUES TO ADVERTISE A RATHER UNSETTLED
PERIOD FOR MUCH OF THE UPCOMING WEEK.

WE ARE AND WILL REMAIN BASICALLY UNDER A MEAN UPPER RIDGE...AND
THE STORM APPROACHING FROM THE WEST WILL TAKE IT/S TIME MOVING
THROUGH. SEVERE OUTLOOK FOR DAY3/WED DOES MENTION NWRN PA...CLOSE
TO THE SFC LOW AND THE BETTER UPPER FLOW. 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...AND IS MUCH CLOSER TO WHAT THE GFS HAS BEEN SAYING ABOUT
THE AIRMASS. THE ZERO C LINE AT 8H SEEMS TO STAY NORTH OF THE STATE
NOW...WITH MODIFICATION TAKING PLACE AS IT IS ALMOST SUMMER IN
CANADA...TOO.
-- End Changed Discussion --

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
A MOIST SERLY FLOW OFF OF THE ATLANTIC OCEAN WILL CONTINUE TO
PRODUCE WIDESPREAD STRATUS IFR-MVFR CIGS ACROSS CENTRAL PA THIS
MORNING WITH CIGS SLOWLY IMPROVING TO ABOVE 1000 FT AT MOST
AIRFIELDS BY 16Z. A BIT OF DRIZZLE AND AREAS OF FOG WILL ALSO ADD TO
LOWER VSBYS AT CIGS BLO 1000 FT AGL THROUGH THE REST OF THIS MORNING
ACROSS NRN AND EASTERN PARTS OF THE STATE...THAT WILL STAY LOCATED
JUST TO THE NORTH OF A QUASI STATIONARY SFC FRONT /EXTENDING FROM
NEAR KYNG TO KAOO AND KTHV AT 13Z/.

THIS BOUNDARY WILL LIFT GRADUALLY NORTH AS A WARM FRONT TODAY AS
THE MEAN SFC-850 MB FLOW SHIFTS TO THE SSW. MDL SOUNDINGS AND SREF
DATA INDICATE PREDOMINATELY VFR CONDS ARE LIKELY EVERYWHERE BY THE
AFTN. HOWEVER...THERE IS A SLIGHT CHC OF AN AFTN TSRA ACROSS THE W
MTNS...WHICH COULD PRODUCE A BRIEF VIS/CIG REDUCTION.

.OUTLOOK...
TUE-THU...LOW CLOUDS/FOG POSS EARLY. SCT PM THUNDERSTORM IMPACTS
POSSIBLE. FRI...NO SIG WX EXPECTED.
-- End Changed Discussion --

&&

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

&&

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