Area Forecast Discussion
Issued by NWS State College, PA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KCTP 260246
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
946 PM EST SUN JAN 25 2015

.SYNOPSIS...
A VIGOROUS UPPER LEVEL STORM WILL SPREAD LIGHT SNOW OVER
PENNSYLVANIA TONIGHT. AN INTENSE SECONDARY COASTAL LOW WILL FORM
OFF THE CAROLINA COAST ON MONDAY. THE COASTAL STORM WILL RIDE
INTO NEW ENGLAND TUESDAY. HIGH PRESSURE WILL BUILD OVER THE REGION
FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER
THURSDAY.

&&

.NEAR TERM /UNTIL 8 AM MONDAY MORNING/...
945 PM UPDATE...
STILL SOME RAIN IN THE S...BUT LIGHT SNOW WITH A THIN SLUSHY COATING
OUT THE OFFICE WINDOW AND AREA WEB CAMS. NO NEED TO TWEAK ANYTHING
FOR THE OVERNIGHT. CONSIDERED ADDING THE NRN TIER INTO THE
ADVY...BUT THE MINOR CHANGE JUST COMES UP WITH TWO 12HR BLOCKS OF
1-3" THERE. WILL LEAVE IT ALONE.

PREV...
WWA/S REMAIN UNCHANGED FOR THE TIME BEING. SNOW JUST BEGINNING TO
PICK UP ACROSS THE S - BUT TEMPS ARE SUCH THAT SOME RAIN IS ALSO
MIXED IN THERE ALONG THE MD BORDER COUNTIES. THEREFORE...THE
ACCUMULATION PROCESS WILL GO SLOWLY THERE AT FIRST. SNOWING
EXTREMELY LIGHTLY OUT THE WINDOW...BUT IT HAS BEEN DOING THAT ALL
DAY. THE DRY AIR AT THE SFC IS DOING AS EXPECTED KEEPING THE
PROGRESSION OF THE SNOW KINDA SLOW FROM S-N. DEWPOINT AT KIDI IS
32F AND ONLY 9F AT KBFD. HAVE MADE ONLY MINOR TWEAKS TO THE
FORECAST - MAINLY TO MENTION MORE RAIN IN THE NEXT FEW HOURS IN
THE S. AS MENTIONED PREVIOUSLY...THE CONSTANT SNOW WILL BE
OCCASIONALLY HEAVY...BUT IN GENERAL...THE ACCUMS THROUGH THE NEXT
12 HRS SHOULD NOT BE A WIDESPREAD 6 HRS ACROSS THE LAURELS/SRN
ALLEGHENIES...MORE LIKE 4-6. THE ACCUMS SHOULD TAPER OFF AS YOU
MOVE S-N ACROSS THE AREA...WITH ONLY AN INCH OR TWO OVERNIGHT IN
THE NE AND ALONG THE NY BORDER.

&&

.SHORT TERM /8 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
945 PM UPDATE...
PRECIP MAY BE A LITTLE LIGHTER...ESP IN THE EAST...THAN WHAT IS
GOING IN THE FCST...SO HAVE MADE A SLIGHT DOWNWARD MOVE TO THE
EAST...BUT IT IS ONLY A HALF INCH OR SO FOR THE DAYTIME ON MONDAY.

PREV...
WEAKENING PRIMARY CLIPPER LOW OVER THE CENTRAL APPALACHIANS TRACKS
SOUTH OF PA MONDAY MORNING WHILE IMPRESSIVE SECONDARY DEVELOPMENT
TAKES PLACE OFF OF THE VA/NC COAST AND RACES NE LATER MONDAY.
STILL CONCERNED FOR WESTERN EDGE OF HEAVY SNOW FALL TO BRUSH MY
FAR SOUTHEAST COUNTIES...WE MAINTAIN A WINTER STORM WATCH FOR YORK
LANCASTER AND LEBANON COUNTIES AS A RESULT FOR AN ADDITIONAL
4-6"+ LATER MONDAY INTO TUESDAY. BUT DURING MONDAY...PERIODS OF
LIGHT SNOW AND SNOW SHOWERS WILL PERSIST THROUGH MOST OF THE DAY.
DEEP EAST FETCH AND UPSLOPE INTO THE LAURELS KEEPS THE SNOWFALL
GOING THROUGH THE AFTERNOON HOURS...WITH DEFORMATION BANDING
LIKELY SETTING UP OVER THE SOUTHEAST LATE IN THE DAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
945 PM UPDATE...
AS WITH MONDAY...THE NEWEST RUN OF THE NAM AND THE 21Z SREF MEAN
QPFS ARE PRACTICALLY DRY FOR THE ERN THIRD OF THE AREA FOR MON
NIGHT AND TUESDAY. IF THESE ARE PERFECT PROGS...LOL...PERHAPS AN
ADVY MAY EVEN BE OVER-DOING IT. HOWEVER...NOT ENOUGH NEW INFO AT
HAND TO CHANGE THE WATCH...WHICH IS GOING TO STAND FOR THE TIME
BEING. MORE 00Z STUFF /GFS AND ECMWF/ WILL COME IN IN A BIT FOR
THE MID SHIFT TO LEARN FROM. HAVE NUDGED QPF AND SNOW DOWN
SLIGHTLY IN THE EAST FOR MON NIGHT AND TUES.

PREV...
HELD ONTO THE WATCH FOR THE FAR SE. OUR EASTERN AREAS WILL
BE CLOSE TO THE HEAVIER SNOW FROM THE COASTAL STORM MONDAY
NIGHT AND TUESDAY MORNING.

STRONGEST WINDS WILL BE EAST OF OUR AREA...BUT GUSTY WINDS
WILL BE LIKELY BY TUESDAY MORNING.

AS NOTED YESTERDAY...THERE WILL BE A LARGE TEMPERATURE
GRADIENT FROM NY TO MD INTO TUE. FRONTAL ZONE RIGHT OVER
THE STATE COLLEGE AREA MUCH OF THE MORNING HERE.

FIRST CONCERN IS THE INVERTED TROUGH TO THE WEST THAT LINGERS
INTO MONDAY NIGHT. DID UP POPS SOME ACROSS THE NW.

SECOND CONCERN IS THE DEEP COASTAL THAT FORMS LATE MONDAY AND
TRACKS NE.

WATCH POSTED FOR THE FAR SE. DID EDGE QPF AND SNOWFALL AMTS
UP SOME ACROSS THE FAR EAST AND SE FOR MONDAY NIGHT AND
EARLY TUE.

WINDS A LITTLE HIGH ON TUE...DID EDGE WIND GUSTS DOWN SOME.

WIND CHILLS MAY REACH ADVISORY LEVELS AT TIMES THIS WEEK...BUT
REAL CONCERN MAINLY STAYS NE OF OUR AREA.

WED STILL LOOKING MAINLY DRY.

ANOTHER FRONT FOR LATE THU INTO EARLY FRIDAY. SECONDARY LOW
FORMS...BUT SITUATION AT THIS POINT NOT LIKE WHAT WE HAVE AT
THE CURRENT TIME.

MORE DETAIL BELOW...

MAIN FOCUS IN THE EXTENDED FCST WILL BE EVOLUTION OF RAPIDLY
DEVELOPING COASTAL LOW EAST OF PA MON NITE AND TUESDAY.

MDL DATA SHOWING A FAIRLY TIGHT RANGE OF SOLUTIONS. 12Z GFS
MAY BE A LITTLE OFF...FROM 12P CHAT ROOM DISC. ANYWAY...MOST OF
THE DATA PLACE OUR EXTREME EASTERN COUNTIES FROM LANCASTER NORTH
THRU SCHUYLKILL CO ON THE WESTERN PERIPHERY OF THE SIGNIFICANT
DEFORMATION BAND SNOW. MDL 7H FGEN FIELDS SEEM TO IMPLY THE HEAVY
SNOW WILL REMAIN JUST EAST OF THE CWA. HOWEVER...GIVEN COMPLEXITY
OF CRITERIA DIFFERENCES ACROSS OUR BORDERS...AND 40% CONFIDENCE OF
AN ADDITIONAL 6 INCHES OR MORE OVER LEBANON/LANCASTER/E YORK
COUNTIES WITH THE SECONDARY LOW...OPTED TO ISSUE WINTER STORM
WATCH FOR THESE THREE COUNTIES FOR MONDAY AFTERNOON THROUGH
TUESDAY MORNING.

ACROSS THE REST OF CENTRAL PA...LIGHT SNOW EXPECTED MONDAY NIGHT
AND TUESDAY ASSOC WITH NEXT SHORTWAVE DIVING INTO DEEPENING UPPER
TROF AXIS OVR PA. TIGHT PRES GRADIENT WEST OF COASTAL LOW SHOULD
RESULT IN A BLUSTERY DAY TUESDAY...BLOWING/DRIFTING SNOW A
POSSIBILITY. BUFKIT SOUNDINGS INDICATE GUSTS TO ARND 30KTS LIKELY.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
KJST AND AOO SOCKED IN WITH VERY LOW CIG/VSBY AND LIGHT TO
MODERATE PRECIP. DOWNSLOPING FARTHER TO THE EAST SHOULD BE ENOUGH
TO KEEP SERN AIRFIELDS /KMDT AND KLNS/ IN VFR/HIGH MVFR CONDS.

AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA TONIGHT
INTO MONDAY...BRINGING ANOTHER ROUND OF SNOW WITH IFR CONDS. THIS
WILL IMPACT MOST TERMINALS AFTER 00Z MONDAY...BUT SOME AFFECTS
POSSIBLE EARLIER AT KJST.

SNOW RAPIDLY OVERSPREADING FROM SW TO NE...BRINGING IFR CONDS TO
THE ENTIRE REGION OVERNIGHT.

SNOW/SNSH CONTINUES MONDAY INTO TUES. NW WINDS PICK UP MON NIGHT
INTO TUES AS LOW PRES SPINS UP OFF NEW ENGLAND COAST. QUIET WX
WEDNESDAY BETWEEN SYSTEMS...BEFORE ANOTHER CLIPPER DROPS ACROSS
THE AREA LATE THU INTO FRI.

OUTLOOK...


MON-MON NIGHT...WIDESPREAD IFR/MVFR IN SNOW/SNSH.
TUE...AREAS MVFR IN SHSN WEST...AND POSS LINGERING SNOW IN THE
EAST.
WED...VFR WITH NO SIG WEATHER EXPECTED.
THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM
THE WEST.
THU NIGHT- FRI...WIDESPREAD IFR/MVFR IN SNOW.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 PM EST MONDAY FOR PAZ010>012-
017>019-024>028-033>036-041-045-046-049>053-056>058-063-064.
WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR PAZ059-065-
066.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR PAZ059-065-066.

&&

$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO/DEVOIR/FITZGERALD
LONG TERM...DANGELO/FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU/EVANEGO



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.