Area Forecast Discussion
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000
FXUS61 KPBZ 231147
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
647 AM EST SUN NOV 23 2014

.SYNOPSIS...
WARMING TREND CONTINUES TODAY...BEFORE A LOW PRESSURE SYSTEM
BRINGS WIDESPREAD RAIN TONIGHT. WINDY AND WARM MONDAY...BEFORE
TURNING SHARPLY COLDER LATE.

&&

.NEAR TERM /THROUGH TONIGHT/...
TEMPS THIS MORNING HAVE LARGELY STAGNATED WITH ABUNDANT CLOUD
COVER AND AT LEAST SOME SOUTHERLY SFC FLOW. READINGS COMMONLY IN
THE MID 40S ARE A FAR CRY FROM 24 HRS AGO WHERE WE HAD MID TO LOW
TEENS.

CURRENT RADAR IMAGERY SHOWS A WEAK WAVE PRODUCING RAIN SHOWERS
ALONG OUR NWRN PERIPHERY. WITH H85 MOISTURE TRANSPORT VECTORS FROM
CURRENTLY 240DEG...EXPECTING PRECIPITATION TO CONTINUE ITS TRACK
ALONG THE NRN 1/3 OF THE CWA. TEMPS WILL CONTINUE TO CLIMB THIS
AFTERNOON UNDER INTENSIFYING SOUTH TO SOUTHEASTERLY FLOW.
EXPECTING DAYTIME HIGHS TO RANGE ABOUT 8-10F ABOVE AVERAGE.

A DEEPENING LOW PUSHES OUT OF THE SRN PLAINS TONIGHT AND IS
EXPECTED TO TRACK THROUGH THE WRN GREAT LAKES BY MON MORNING. AS
THE LOW MOVES UP THE MS VALLEY IT WILL GATHER COPIOUS GULF
MOISTURE THAT WILL OVERSPREAD THE FORECAST AREA TONIGHT WITH A
WARM FRONT. STRONG SE FLOW JUST ABOVE THE SFC...IN THE FORM OF A
60+ KT H85 JET...WILL SET UP DOWNSLOPING FROM THE RIDGES AND
COULD DELAY THE ONSET OF RAIN BY AN HOUR OR TWO. BY 03Z
MON...HOWEVER...RAINSHOWERS WILL OVERSPREAD THE ENTIRE FORECAST
AREA AS THE LOW PIVOTS NORTH ACROSS LAKE MICHIGAN. ALTHOUGH THE
STOUT H85 JET PERSISTS FOR SEVERAL HOURS ACROSS THE RIDGES BETWEEN
00-06Z...THE BL SHOULD DECOUPLE ENOUGH TO KEEP THE HIGHEST WINDS
ALOFT. EXPECTING TO SEE SOME GUSTY WINDS IN THE 20-30KT
RANGE...BUT WILL NOT BE ISSUING A WIND ADVISORY AT THIS TIME.
TAX

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
SURFACE WARM FRONT WILL LIFT QUICKLY THROUGH THE CWA EARLY MONDAY
MORNING IN RESPONSE TO SURFACE LOW PRESSURE SURGING THROUGH THE
GREAT LAKES INTO WESTERN ONTARIO. LARGE SCALE ASCENT AND ATTENDANT
PRECIPITATION SHOULD RAPIDLY END FROM SOUTH TO NORTH AROUND 12Z AS
PSEUDO-CAPPED WARM SECTOR AIRMASS SPREADS INTO THE AREA. WITH THE
LARGE SCALE MOISTURE SURGE...COULD SEE SOME DRIZZLE OR SPOTTY
SHOWERS EARLY...BUT OTHERWISE DEEP MECHANICAL MIXING SHOULD PROMOTE
AT LEAST PARTIAL CLEARING ACROSS THE CWA BY MID-LATE MORNING. BEST
CHANCE FOR SUNSHINE (AND LONGEST WARM SECTOR DURATION) WILL BE EAST
OF A ZANESVILLE TO NEW CASTLE LINE...WHERE TEMPERATURES SHOULD TOP
OUT AT OR ABOVE 60 DEGREES UNDER GUSTY SOUTH WINDS THAT WILL USHER
IN SOME SEASONABLY HUMID AIR AS WELL.

MODELS LARGELY AGREE WITH THE DEPICTION OF A PRE-FRONTAL TROUGH THAT
WILL ADVANCE EASTWARD ACROSS THE CWA BETWEEN 19-23Z...SIGNALING THE
ARRIVAL OF ANOTHER STRONG ARCTIC COLD FRONT. EVEN IF WE POKE INTO
THE 60S...SURFACE BASED INSTABILITY LOOKS RATHER MEAGER GIVEN MODEST
LAPSE RATES AND AMPLE DEEP LAYER MOISTURE. THUNDER CHANCES LOOK
LOW...BUT STRONG FRONTAL ASCENT COULD YIELD A BROKEN NARROW
COLD-FRONTAL RAINBAND (SQUALL) DURING THE EARLY-MID AFTERNOON
FRONTAL PUSH. GIVEN THE PRESENCE OF 70-80 KNOTS OF MID LEVEL
FLOW...WE COULD SEE SOME STRONG CONVECTIVE GUSTS ALONG AND
IMMEDIATELY BEHIND THE COLD FRONT IF THIS FEATURE MATERIALIZES.

TEMPERATURES WILL FALL SHARPLY LATE MONDAY INTO MONDAY NIGHT. DEEP
LAYER CYCLONIC FLOW WILL PERSIST AHEAD OF THE UPPER TROUGH
AXIS...WHICH WILL MAINTAIN CLOUDY SKIES AND THE POTENTIAL FOR WIDELY
SCATTERED SNOW SHOWERS AS SEVERAL EMBEDDED MID LEVEL IMPULSES MOVE
THROUGH THE UPPER JET AXIS. LOW LEVEL FLOW TRAJECTORIES LOOK POOR
FOR LAKE-EFFECT SNOWS UNTIL LATER TUESDAY...AND EVEN THEN WOULD BE
AIMED ACROSS WESTERN NY.

BOOKBINDER

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS THE COLD FRONT SHIFTS TOWARD THE COAST ON WEDNESDAY...A STRONG
SOUTHEAST COASTAL LOW IS EXPECTED TO MATURE QUICKLY AND MOVE NORTH
OR NORTHEAST ALONG THE EXISTING BAROCLINIC ZONE. MODELS BEGIN TO
DIVERGE STRONGLY IN THIS PERIOD. THE ECMWF DEVELOPS A MAJOR STORM
INSIDE THE 40N/70W BENCHMARK...WHILE THE GFS IS QUICKER...WITH AN
OPEN WAVE GOING OUT TO SEA AND FAILING TO LATCH ONTO THE STRONG
THERMAL GRADIENT. THE TRACK AND INTENSITY OF THIS SYSTEM COULD HAVE
MAJOR IMPLICATIONS ON WEDNESDAY AFTERNOON AND EVENING TRAVEL TO AND
FROM THE EAST COAST...ESPECIALLY THE INTERIOR AIRPORTS AND HIGHWAYS
WHERE SNOW ACCUMULATIONS COULD BE SIGNIFICANT IF STRONGER MODEL
SOLUTIONS VERIFY.

DO NOT EXPECT ANY IMPACTS ACROSS THE LOCAL CWA...BUT GIVEN THE HIGH
DEGREE OF UNCERTAINTY WITH THIS POTENTIAL STORM...FOLKS TRAVELING TO
OR FROM THE EAST SHOULD CLOSELY MONITOR FORECASTS.

OTHERWISE...A PERIOD OF MUCH BELOW NORMAL TEMPERATURES WILL RETURN
FOR TUESDAY AND CONTINUE FOR THE BALANCE OF THE WEEK...INCLUDING THE
THANKSGIVING HOLIDAY. PRESENTLY DO NOT SEE ANY SIGNIFICANT
PRECIPITATION CHANCES THROUGH THE PERIOD...ALTHOUGH A PROGRESSIVE
CLIPPER-LIKE WAVE COULD BRING A BRIEF BOUT OF SNOW TO THE REGION
THURSDAY AND/OR FRIDAY.

BOOKBINDER

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
GENERALLY VFR CONDITIONS TODAY WITH LIGHT SRLY SFC WINDS. AS A
WARM FRONT APPROACHES TONIGHT...WIDESPREAD RAIN SHOWERS ARE
EXPECTED WITH INCREASING SERLY FLOW. EXPECTING MVFR RESTRICTIONS
LATE TONIGHT INTO MON MORNING WITH WARM FRONT RAIN...SOME DROPS TO
IFR ARE POSSIBLE...MAINLY FOR THE NRN TERMINALS. GUSTY SRLY WINDS
EXPECTED TO THEN PERSIST INTO MON.
TAX

OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
POSSIBLE RESTRICTIONS THURSDAY IN SNOW SHOWERS.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$





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