-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 270004
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
804 PM EDT SAT JUL 26 2014

.SYNOPSIS...
A SERIES OF DISTURBANCES WILL MOVE ACROSS THE FORECAST AREA
THE SECOND HALF OF THIS WEEKEND AS A DEEP UPPER TROUGH DEVELOPS
OVER THE NORTHEASTERN UNITED STATES. THERE WILL BE SEVERAL CHANCES
FOR PRECIPITATION...INCLUDING STRONG TO POTENTIALLY SEVERE
THUNDERSTORMS SUNDAY INTO SUNDAY NIGHT...BEFORE ANOTHER SHOT OF
UNSEASONABLY COOL AIR MOVES IN AND REMAINS OVER THE REGION
THROUGHOUT THE NEW WORK WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
MOISTURE FLUX CONVERGENCE INTO EASTERN OH AND WESTERN PA AHEAD OF
SEVERAL SHORTWAVE TROFS IS MAINTAINING A LARGE AREA OF SHOWERS AND
EMBEDDED THUNDERSTORMS. MOST ACTIVE CONVECTION IS NOW APPROACHING
SOUTHERN PORTIONS OF THE LAUREL HIGHLANDS AND WEST CENTRAL
MOUNTAINS WITH SOME HEAVY DOWNPOURS AND LIKELY SUB SEVERE WIND
GUSTS. SLOW DECREASE IN STRENGTH IS ANTICIPATED THROUGH THE
EVENING AS DAYTIME HEATING IS LOST BUT LL CONVERGENCE MAINTAINS
THE OVERALL AREA OF CONVECTION SPREADING EASTWARD.

GOING FORECAST IN GOOD SHAPE THIS EVENING FOR CURRENT RADAR
TRENDS. NO SIG UPDATES AT THIS TIME.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY SHAPING UP TO BE A POTENTIALLY BUSY DAY AS AN UNSEASONABLY
STRONG UPPER LOW DROPS THROUGH THE LOWER LAKES AND TAKES AIM AT
THE LOCAL AREA. SPC HAS OUTLOOKED REGION JUST TO OUR SW /INCLUDING
PORTIONS OF OH-KY-WV/ WITH A MODERATE RISK WHICH LOOKS REASONABLE
GIVEN THE STRENGTH OF THE APPROACHING DYNAMICS AND INSTABILITY. WE
COULD BE VULNERABLE LOCALLY INTO THE EVENING GIVEN THE EXPECTED
TIMING OF THE COLD FRONT ENTERING THE REGION AND THE AMOUNT OF
UPSTREAM INSTABILITY/SHEAR THE SYSTEM WILL HAVE AVAILABLE.

WHERE THE OHIO VALLEY DEVELOPMENTS TAKE PLACE TONIGHT WILL HAVE
MUCH TO SAY ABOUT HOW FAR NORTH INTO CENTRAL PA THE STRONGEST
STORMS WILL MANAGE TO MOVE. BUT THIS SYSTEM IS ROBUST ENOUGH THAT
WE MAY INITIALLY SEE ONE WAVE OF STORMS DEVELOP ACROSS THE SOUTH
DURING THE DAY...WITH A SECOND WAVE DEVELOPING FURTHER NORTH LATE
IN THE AFTERNOON INTO THE EVENING. THE SOUTHERN STORMS LOOK TO
HAVE THE HIGHEST POTENTIAL FOR LARGE HAIL/DAMAGING WINDS/EVEN AN
ISO TORNADO...WITH NORTHERN STORMS MAINLY WIND PRODUCERS.

FIRST HALF OF THE EVENING SHOULD STILL BE QUITE BUSY WITH ONGOING
STORMS...WITH DECREASING ACTIVITY INTO THE OVERNIGHT BEHIND THE
COLD FRONT.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
RAINFALL WILL DIMINISH IN COVERAGE MONDAY AS THE FRONTAL BOUNDARY
MOVES EAST OF THE AREA. LINGERING SHOWERS ARE MOST LIKELY OVER
EASTERN PA WITH THE WESTERN CWA DRYING OUT.

A DEEP TROUGH OVER THE EASTERN US WILL CONTINUE THROUGH THE
UPCOMING WEEK...WITH THE AXIS WAFFLING EAST TO WEST AS INDIVIDUAL
SHORT WAVES MOVE THROUGH. ONLY PAINTED ISOLATED SHOWERS IN THE
LONG TERM AS SPECIFICS WILL DEPEND ON THE DAY TO DAY LOCATION OF
RIPPLES MOVING THROUGH THE TROUGH.

WE COULD SEE MORE SIGNIFICANT MOISTURE RETURN NEXT WEEKEND AS THE
GFS/GEFS/ECMWF ALL HINT AT THE UPPER TROUGH RETROGRADING A
BIT...PAVING THE WAY FOR A SOUTH TO SOUTHEAST FETCH OF ATLANTIC
MOISTURE WORKING INTO THE NORTHEAST.

500MB HEIGHTS IN THE 3-4STD DEV BELOW NORMAL RANGE AND 850 TEMPS
OF 1-3 STD DEV BELOW NORMAL POINT TO THE MOST CERTAIN PART OF THE
FORECAST BEING SEVERAL DAYS OF TEMPERATURES AVERAGING WELL BELOW
NORMAL. A SLOW MODERATION CAN BE EXPECTED BY LATE IN THE WEEK.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
TROUGH OF LOW PRES APPROACHING FROM THE GRT LKS WILL SPREAD SCT
SHRA AND A FEW TSRA INTO CENTRAL PA OVERNIGHT. RADAR AT 00Z SHOWS
FIRST BATCH OF SHRA/TSRA MOVING THRU SW PA...WITH ADDITIONAL
ACTIVITY LIKELY TO FOLLOW LATER TONIGHT. FOR MOST OF CENTRAL
PA...THE BEST CHC OF PRECIP WILL COME BTWN 04Z-09Z WITH PASSAGE OF
UPPER TROUGH. BRIEF VIS REDUCTIONS ARE POSSIBLE IN ANY SHRA/TSRA.
HOWEVER...THE LARGER AVIATION CONCERN IS THE POSSIBILITY OF LOW
CIGS DEVELOPING TOWARD DAWN AT KBFD...THE RESULT OF INCREASING LOW
LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA. A BAND OF
MODERATELY STRONG WINDS ALOFT PRECEDING THE TROUGH COULD PRODUCE
MARGINAL LLWS OVERNIGHT...MAINLY OVR THE NW MTNS.

ANY EARLY LOW CIGS SHOULD MIX OUT OVR THE N MTNS ON SUNDAY...LEAVING
WIDESPREAD VFR CONDS FOR THE REST OF THE DAY. MAIN AVIATION CONCERN
WILL COME LATE SUNDAY AND SUNDAY NIGHT...AS A POTENT LOW PRES
SYSTEM APPROACHES FROM THE GRT LKS. LATEST MDL DATA POINTS TOWARD
THE POSSIBILITY OF SOME STRONG TSRA ACROSS SOUTHERN PA DURING THE
LATE AFTN AND EVENING. FURTHER NORTH...THE THREAT OF STRONG WGUSTS
IS LOWER. HOWEVER...VSBY REDUCTIONS STILL APPEAR LIKELY IN
SHRA/TSRA SUNDAY NIGHT.

OUTLOOK...

MON...AM LOW CIG POSS W MTNS.
TUE-THU...NO SIG WX EXPECTED.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...RXR
NEAR TERM...DEVOIR/RXR
SHORT TERM...RXR
LONG TERM...LA CORTE/TYBURSKI
AVIATION...FITZGERALD