475
FXUS61 KCTP 181007
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
507 AM EST MON NOV 18 2024
SYNOPSIS
A WEAK COLD FRONT OVER LAKES ERIE AND ONTARIO EARLY TODAY WILL
DRIFT INTO THE NORTHERN TIER COUNTIES OF PA THIS MORNING
ACCOMPANIED BY NOTHING MORE THAN A FEW LIGHT SHOWERS.
RIDGING WILL BUILD OVER THE STATE LATE TODAY AND TONIGHT. AS
THE RIDGE MOVES EAST ON TUESDAY, A WARM FRONT WILL LIFT
NORTHEAST ACROSS THE REGION WITH CLOUDS AND SCATTERED SHOWERS
INTO EARLY WEDNESDAY.
A DEEP, ANOMALOUSLY COLD CUT-OFF UPPER LOW WILL TRACK ACROSS
FROM THE GREAT LAKES INTO PENNSYLVANIA LATE THIS WEEK, PRECEDED
BY AN OCCLUDED FRONT PASSAGE WEDNESDAY NIGHT.
NEAR TERM /UNTIL 6 PM THIS EVENING/
THE MAIN WEATHER FEATURE EARLY TODAY IS A DYING COLD FRONT
DRIFTING ACROSS WESTERN NY WITH ITS SOUTHERN EXTENT NEAR KERI
AND KCLE AT 0930Z. THE BULK OF ANY LIGHT SHOWERS IS RACING OFF
TO THE EAST BENEATH THE THERMALLY INDIRECT ASCENDING BRANCH OF A
POTENT, 135 KT ULVL JET MAX WITH ITS AXIS FROM KCLE TO KPBZ AND
KTHV.
A PERIOD OF BKN-OVC SHALLOW STRATO THIS MORNING SHOULD DISSIPATE
FOR THE MIDDAY AND AFTERNOON HOURS AS THE DESCENDING BRANCH
(ASSOCIATED WITH LEFT ENTRANCE REGION) SLIDES ACROSS THE CWA.
WEST-NW WIND GUSTS WILL INCREASE TO THE MID AND UPPER TEENS WITH
THE PASSAGE OF THE DESCENDING BRANCH OF THE JET.
TEMPS HAVE BEEN NEARLY STEADY, AND IN SOME CASES ROSE A FEW DEG
F OVERNIGHT WITH READING AT DAWN EXPECTED TO RANGE FROM THE MID
AND 30S IN THE COLDER SPOTS OF THE MIDDLE SUSQ VALLEY, TO
BETWEEN 45 AND 50 DEGREES THE NW MTNS/LAUREL HIGHLANDS.
LOW LEVEL MOISTURE POOLING AHEAD OF THE FRONT, COMBINED WITH AN
UPSLOPING WESTERLY FLOW, SHOULD YIELD STRATUS ACROSS THE
ALLEGHENY PLATEAU, WHICH WILL TEND TO CLEAR FROM NORTH TO SOUTH,
AS DRIER AIR ARRIVES BEHIND THE FRONT. SUBSIDENCE TO THE LEE OF
THE ALLEGHENIES SHOULD RESULT IN MAINLY SUNNY SKIES ACROSS THE
EASTERN HALF OF THE FORECAST AREA MONDAY.
THE AIR MASS ALONG AND IMMEDIATELY BEHIND THE FRONT COLD FRONT
WILL BE WELL ABOVE AVERAGE AND INCREASING SUNSHINE SHOULD PUSH
AFTERNOON READINGS INTO THE 55-65F RANGE (+10-15 DEGREES ABOVE
THE HISTORICAL AVERAGE).
SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/
UPPER LEVEL RIDGING OVER THE AREA SHOULD PROVIDE CENTRAL PA
WITH MILD AND RAIN-FREE CONDITIONS TONIGHT AND MOST IF NOT ALL
OF TUESDAY. HOWEVER, WARM ADVECTION ASSOCIATED WITH A WEAKENING
SHORTWAVE LIFTING INTO THE GRT LKS SHOULD LEAD TO INCREASING
CLOUDS LATE TUESDAY/TUESDAY NIGHT WITH THE CHANCE OF A FEW
SHOWERS, MAINLY OVER THE W MTNS.
FOCUS THEN SHIFTS TO A CUT-OFF UPPER LOW DROPPING INTO THE
MIDWEST. MODEL SOUNDINGS INDICATE AN EASTERLY FLOW OFF OF THE
ATLANTIC WILL LIKELY YIELD STRATUS OVER PARTS OF THE AREA WED,
ESPECIALLY OVER THE CENTRAL MTNS. FALLING HEIGHTS AND SURGING
PWATS ALONG A SOUTHERLY LOW LEVEL JET SHOULD THEN BRING
THICKENING CLOUDS AND AN INCREASING CHANCE OF SHOWERS ACROSS THE
ENTIRE AREA BY LATE WEDNESDAY OR WED EVENING. WE MAY NEED TO
EVENTUALLY UNDERCUT NBM MAX TEMPS WED, DUE ITS WARM BIAS IN
EASTERLY FLOW/CAD SCENARIOS.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
RECENT GUIDANCE ALL TRACKS A SURFACE COLD/OCCLUDED FRONT THROUGH
CENTRAL PA WED NIGHT IN ADVANCE OF AN UPPER LOW APPROACHING
FROM THE GRT LKS. STRONG LARGE SCALE FORCING AHEAD OF THE UPPER
LOW AND LOW LEVEL CONVERGENCE ALONG THE FRONT SUPPORTS A HIGH
CHANCE OF RAIN SHOWERS WED NIGHT. HOWEVER, PLENTY OF SPREAD
REMAINS WITH REGARD TO RAIN AMOUNTS. ENSEMBLE MEAN QPF IS IN THE
0.25 TO 0.60 INCH RANGE. HOWEVER, A DECENT NUMBER OF EPS
MEMBERS PRODUCE TOTALS >1 INCH ASSOCIATED WITH THE POTENTIAL OF
DEEPER GOMEX MOISTURE STREAMING NORTH AHEAD OF THE FRONT.
CURRENT GUIDANCE INDICATES A DRY SLOT WILL WORK INTO CENTRAL PA
THU MORNING, THEN A PERIOD OF CHILLY AND UNSETTLED WEATHER LOOKS
VERY LIKELY LATE THIS WEEK, AS THE UPPER LOW TRACKS ACROSS OR
JUST NORTH OF PA. A DEEP MOIST NORTHWEST FLOW ON THE WESTERN
PERIPHERY OF THE EXITING UPPER LOW SHOULD RESULT IN PERSISTENT
LAKE-ENHANCED, OROGRAPHIC PRECIPITATION FOCUSED OVER THE W MTNS
THURSDAY NIGHT INTO AT LEAST THE FIRST HALF OF NEXT WEEKEND.
MODEL THERMAL PROFILES CURRENTLY LOOK COLD ENOUGH TO SUPPORT THE
FIRST ACCUMULATING SNOW OF THE SEASON ACROSS THE HIGHER
ELEVATIONS OF THE ALLEGHENIES BETWEEN THU NIGHT AND SATURDAY,
BUT SNOWFLAKES COULD EXTEND SOUTHEAST OF THE ALLEGHENY FRONT AT
TIMES.
IN ADDITION TO FREQUENT PRECIPITATION AND BELOW NORMAL DAYTIME
TEMPERATURES, GUSTY WEST-NORTHWEST WINDS ARE ALSO ANTICIPATED
FRIDAY AND SATURDAY, AS A TIGHT GRADIENT DEVELOPS WEST OF AN
INTENSIFYING SURFACE LOW OVER EASTERN NEW ENGLAND. LATEST EPS
PLUMES INDICATE GUSTS OF 30-35MPH ARE LIKELY BOTH DAYS.
PERSISTENT CLOUD COVER AND COOLER TEMPERATURES ALOFT WILL KEEP
HIGH TEMPERATURES IN THE UPPER 30S TO NEAR 50F, WHICH WILL BE A
SIGNIFICANT CHANGE, BUT IS STILL ONLY A FEW DEGREES BELOW
NORMAL FOR THIS TIME OF YEAR.
AVIATION /10Z MONDAY THROUGH FRIDAY/
MID SHIFT UPDATE.
WINDS DID KICK UP FOR A BRIEF TIME.
OTHER ISSUE IS LOWER CIGS CAME FURTHER SOUTH.
THUS UPDATES DONE FOR THESE FACTORS.
EARLIER DISCUSSION BELOW.
06Z TAFS SENT.
LACK OF MIXING SUNDAY KEPT TEMPERATURES ON THE COOL SIDE, TOO
WARM ALOFT TO MIX, AFTER A COLD START WHEN I LEFT SUNDAY
MORNING.
JUST ENOUGH OF A BREEZE NOW TO THE WEST AND NORTH TO BRING
TEMPERATURES UP NICELY. UP 3 DEGREES ON THE ROOF HERE IN THE
PAST HOUR. MAIN POTENTIAL FOR ANY FOG THE NEXT FEW HOURS WOULD
BE AT SITES LIKE LNS AND MDT, WHERE WINDS ARE LIGHTER, BUT LEFT
FOG OUT, LOW CHC. BORDERLINE FOR LLWS, LEFT OUT FOR NOW, AS SFC
WINDS SLOWLY CREEPING UP.
MAIN THING OF INTEREST ON THE RADAR IS BAND OF HIGH CLOUDS FROM
NEAR AVP, SOUTHWARD TO NEAR PIT. COULD SEE THIS FEATURE NICELY
WHEN I LEFT MY PLACE LATE THIS EVENING TO COME IN, WITH MOON
BREAKING THROUGH THE DECK.
ABOUT THE ONLY CHANCE FOR LOWER CIGS AND MAYBE A FEW LIGHT
SHOWERS WOULD BE BFD THIS MORNING. PERHAPS AT JST JUST AFTER
SUNRISE. THE AIRMASS QUITE DRY FOR LOWER CLOUDS.
MID AND HIGH CLOUDS START TO WORK BACK TO THE NORTH AND EAST
MONDAY NIGHT, AS THE AREA OF HIGH PRESSURE MOVES EAST OF THE
AREA.
OUTLOOK...
TUE...MAINLY DRY WITH VFR CONDITIONS.
WED...RESTRICTIONS POSS, MAINLY NW. MORE WIDESPREAD
RESTRICTIONS WITH RAIN AND LLWS WED NIGHT.
THU-FRI...RESTRICTIONS LIKELY WITH RAIN AND SNOW SHOWERS, MAINLY
ACROSS THE MOUNTAINS. WINDY.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT/FITZGERALD
NEAR TERM...LAMBERT/FITZGERALD
SHORT TERM...LAMBERT/FITZGERALD/BANGHOFF
LONG TERM...FITZGERALD/BANGHOFF
AVIATION...MARTIN
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