122
FXUS61 KCTP 170956
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
456 AM EST SUN NOV 17 2024
SYNOPSIS
A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT WILL BE
CENTERED OVER THE STATE TODAY BRINGING FAIR, DRY CONDITIONS
WITH LIGHT WIND AND MILD TEMPERATURES SOME 5 TO 10 DEGREES
ABOVE NORMAL FOR MID NOVEMBER.
A WEAK COLD FRONT WILL SLIDE ACROSS THE NORTH LATE TONIGHT
NIGHT INTO MONDAY POSSIBLY ACCOMPANIED BY A BRIEF SHOWER OR
TWO, NEAR AND NORTH OF THE ROUTE 6 CORRIDOR.
MAINLY DRY CONDITIONS FOR MONDAY AND MUCH OF TUESDAY.
THE NEXT CHANCE FOR WIDESPREAD PRECIPITATION WILL COME IN THE
FORM OF WIDESPREAD RAIN SHOWERS WEDNESDAY NIGHT INTO THURSDAY,
THEN A LIKELY CHANGEOVER TO SNOW ACROSS THE HIGHER TERRAIN OF
NORTHERN AND WESTERN PA FOR LATER THURSDAY THROUGH FRIDAY WITH
A MIX OF RAIN AND WET SNOW SHOWERS IN THE VALLEYS.
NEAR TERM /THROUGH TONIGHT/
A NORTH/SOUTH SURFACE HIGH PRESSURE RIDGE WAS LOCATED ACROSS
WESTERN PA EARLY TODAY. THIS WEATHER FEATURE AND A LIGHT FLOW OF
SHALLOW MOISTURE OFF LAKE ERIE WILL TRAP SOME LOW CLOUDS ACROSS
THE NW/WCENT MOUNTAINS EARLY TODAY.
AS THE RIDGE DRIFTS SLOWLY EAST ACROSS THE COMMONWEALTH TODAY
AND THE LOW-LEVEL FLOW BECOMES LIGHT AND VARIABLE OR LIGHT
SOUTHERLY IN DIRECTION, THE AFOREMENTIONED LOW CLOUDS WILL
GRADUALLY DISSIPATE LATE THIS MORNING.
MILDER AIR STREAMING EAST AT MID AND UPPER LEVELS OF THE
ATMOSPHERE WILL HELP TO FORM/ADVECT AN EXTENSIVE SHIELD OF
CIRRUS TODAY (AND SOME ALTO CU ACROSS THE WEST LATE THIS
AFTERNOON/EVENING). THE CIRRUS WILL BE THICK ENOUGH TO DIM OR
EVEN BLOCK THE LOW ANGLE SUN AT TIMES TODAY, AND ITS ONSET
TIMING WILL MAKE IT PRUDENT TO TRIM MAX TEMPS BY A FEW DEG,
FOLLOWING THE DECENT AMOUNT OF RADIATIONAL COOLING UNDER MAINLY
CLEAR SKIES OVERNIGHT/EARLY TODAY.
EXPECT MAX TEMPS TO VARY FROM THE UPPER 40S ACROSS THE HIGH
TERRAIN OF THE NORTH AND WEST TO THE LOW AND MID 50S ACROSS MUCH
OF THE REMAINDER OF CENTRAL PA. SOME UPPER 50S ARE STILL
POSSIBLE ACROSS THE FAR SE ZONES WHERE THE LONGEST DURATION OF
SUNSHINE WILL OCCUR BEFORE THE HIGH CLOUDS BEGIN TO THICKEN UP.
A RATHER EXTENSIVE AND THICK SHIELD OF MID AND HIGH CLOUDS
TONIGHT WILL LEAD TO MIN TEMPS IN THE UPPER 30S (EAST) TO MID
40S (SW MTNS) WHICH WILL BE A HEALTHY 8-15 DEG F ABOVE NORMAL.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
A NORTHERN STREAM SHORTWAVE WILL PIVOT ACROSS THE EASTERN GREAT
LAKES INTO THE NEW ENGLAND STATE FOR LATE TONIGHT INTO EARLY
MONDAY.
THIS FEATURE WILL SEND A WEAK COLD FRONT THROUGH THE REGION AND
TRIGGER SOME LIGHT RAIN SHOWERS DOWNWIND OF LAKE ERIE CLOSE
NEAR AND TO THE NORTH OF THE NY BORDER. RIDGING SFC AND ALOFT
RETURNS FOR THE REST OF MONDAY, BRINGING DRY CONDITIONS WITH
MILDER DAYTIME TEMPERATURES IN THE 55-65F RANGE (+10-15 DEGREES
ABOVE THE HISTORICAL AVERAGE).
UPPER LEVEL RIDGING OVER PA SHOULD PROVIDE AT LEAST THE CENTRAL
AND EASTERN ZONES WITH MILD AND MOSTLY RAIN-FREE CONDITIONS FOR
THE BULK OF TUESDAY. HOWEVER, WARM ADVECTION ASSOCIATED WITH A
WEAKENING SHORTWAVE LIFTING INTO THE GRT LKS MAY LEAD TO
INCREASING LATE AFTERNOON/EVENING CLOUDS AND PERHAPS A FEW
SHOWERS, MAINLY OVER THE NW MTNS. FOCUS THEN SHIFTS TO A CUT-
OFF UPPER LOW DROPPING INTO THE MIDWEST.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
OUR SUITE OF ENSEMBLE PREDICTION SYSTEMS IS IN GENERALLY GOOD
AGREEMENT ON THE LARGE-SCALE PATTERN NEXT WEEK, LEADING TO
REASONABLY HIGH CONFIDENCE.
THE PATTERN LOOKS TO BECOME MORE AMPLIFIED, AS A DEEPENING UPPER
LOW AND TRAILING TROUGH AXIS DIGS INTO THE EASTERN GREAT LAKES
AND NORTHEASTERN STATES. THIS EVOLUTION IS STILL EXPECTED TO
BRING A STRONG COLD FRONT ACROSS THE COMMONWEALTH DURING THE
MID-WEEK PERIOD, ACCOMPANIED BY WIDESPREAD SHOWERS, WITH OUR
COLDEST AIR MASS OF THE SEASON THUS FAR TO FOLLOW FOR THE END OF
THE WEEK INTO NEXT WEEKEND.
GIVEN THE AFOREMENTIONED COLD AIR, ALONG WITH WELL ABOVE NORMAL
WATER TEMPERATURES ON THE GREAT LAKES, THE STAGE IS SET FOR A
PROLONGED PERIOD OF LAKE ENHANCED AND UPSLOPE SHOWERS. MUCH OF
THESE SHOWERS SHOULD BE IN THE FORM OF SNOW OVER THE HIGHER
TERRAIN OF THE ALLEGHENIES, WITH A RAIN AND WET SNOW MIX
ANTICIPATED IN THE VALLEYS FARTHER EAST AND SOUTH. ALTHOUGH IT
IS TOO EARLY TO START TALKING ABOUT ACCUMULATIONS, IT DOES
APPEAR QUITE PROBABLE THAT THE GROUND WILL BE WHITENED OVER THE
ELEVATED TERRAIN OF NORTHWESTERN PA, ALONG WITH PARTS OF THE
LAUREL HIGHLANDS.
THE AFOREMENTIONED UPPER LOW WILL BE SLOW TO LIFT OUT, SO FAIRLY
COLD TEMPERATURES WILL PROBABLY NOT MODERATE MUCH UNTIL THE
EARLY PART OF THE FOLLOWING WEEK.
AVIATION /09Z SUNDAY THROUGH THURSDAY/
MAINLY CLEAR OUTSIDE THE OFFICE WHEN I CAME IN AT 1130, BUT I
COULD SEE SOME LOWER CLOUDS WELL TO THE WEST. NOT REALLY SOLD
ON FOG LATER AT BFD AND OTHER SITES, BUT WILL HOLD ONTO IT FOR
NOW, AS WE DID GET A BIT OF RAIN LATELY. THUS NO BIG CHANGES
FOR THE 06Z TAF PACKAGE AT THIS POINT. OVERALL REALLY GOOD
WEATHER THE NEXT FEW DAYS FOR MID NOVEMBER.
EARLIER DISCUSSION BELOW.
MVFR CEILINGS CONTINUE AT BFD AND UNV THIS EVENING, WHILE THE
REST OF CENTRAL PENNSYLVANIA IS CURRENTLY VFR. VFR CONDITIONS
ARE EXPECTED TO CONTINUE THROUGH THE NIGHT EAST OF UNV, WHILE
AREAS TO THE WEST WILL SEE CEILING AND VISIBILITY RESTRICTIONS
DEVELOP. MODEL SOUNDINGS SUGGEST THAT AS UPPER LEVEL RIDGING
BUILDS IN FROM THE WEST, LOW LEVEL MOISTURE WILL BECOME TRAPPED
BENEATH A SUBSIDENCE INVERSION. THIS WILL LEAD TO IFR/LIFR
CEILINGS AT BFD AND JST, AS WELL AS THE POTENTIAL FOR IFR/LIFR
VISIBILITIES. WHILE CONFIDENCE IN LOW CLOUDS AND FOG IS HIGHEST
AT BFD/JST (80-90%), IT IS POSSIBLE THAT FOG DEVELOPS FARTHER TO
THE EAST AS WELL (AOO/UNV/IPT). THERE IS A MUCH LOWER CHANCE OF
ANY FOG DEVELOPING AT MDT/LNS.
FOG AND LOW CLOUDS WILL GRADUALLY DISSIPATE DURING THE MORNING
AND WILL GIVE WAY TO VFR CONDITIONS AREA-WIDE BY THE AFTERNOON.
WINDS WILL BE LIGHT THROUGH THE 00Z TAF PERIOD, WITH WEST-
NORTHWEST WINDS AROUND 3-5 KNOTS.
OUTLOOK...
SUN NIGHT - EARLY MON...CFROPA. MVFR CIGS/VIS IN -SHRA, MAINLY
N HALF.
MON PM-TUES...NW FLOW. IFR/MVFR CIGS NW, VFR SE.
WED...RESTRICTIONS POSS, MAINLY NW. MORE WIDESPREAD RESTRICTIONS
WITH RAIN AND LLWS WED NIGHT.
THU...RESTRICTIONS LIKELY WITH RAIN AND SNOW SHOWERS.
FIRE WEATHER
THE FIRE WEATHER WATCH HAS BEEN CANCELLED AS CONFIDENCE HAS
INCREASED THAT RH VALUES WILL REMAIN ABOVE 30 PERCENT ACROSS THE
AREA PREVIOUSLY IN THE WATCH. ALTHOUGH CRITICAL FIRE WEATHER
CONDITIONS ARE NO LONGER EXPECTED, THERE IS STILL AN INCREASED
RISK OF WILDFIRE SPREAD AND A SPECIAL WEATHER STATEMENT HAS BEEN
ISSUED TO DISCUSS THIS RISK. FOR AREAS EAST OF THE SUSQUEHANNA
RIVER, MINIMUM RELATIVE HUMIDITY VALUES WILL RANGE FROM THE
UPPER 30S TO THE LOW 40S PERCENT ACCOMPANIED BY WIND GUSTS
BETWEEN 25 AND 35 MPH. THE LOWEST RH VALUES ARE EXPECTED IN
EASTERN SCHUYLKILL COUNTIES, WHERE THEY MAY BRIEFLY DROP TO
NEAR 30 PERCENT (35 PERCENT CHANCE). THE 1-HR AND 10-HR FUEL
MOISTURES ARE ALSO ABOVE CRITICAL LEVELS, EXPECTED TO REMAIN
ABOVE 10 PERCENT TODAY PER DCNR REPORTS.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT
NEAR TERM...JUREWICZ/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...JUREWICZ/FITZGERALD/NPB
AVIATION...MARTIN/BAUCO
FIRE WEATHER...COLBERT
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