Area Forecast Discussion
Issued by NWS Albany, NY

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000
FXUS61 KALY 200840
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
340 AM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL GRADUALLY BUILD INTO THE NORTHEAST AT THE SURFACE
FOR THE WEEKEND...SLIDING OFFSHORE MONDAY. WEAK UPPER LEVEL
DISTURBANCES WILL CROSS THE REGION THIS WEEKEND AS WELL WITH
AREAS OF CLOUDS. MONDAY NIGHT AND TUESDAY A STORM WILL ORGANIZE
IN THE GREAT PLAINS WITH AN INCREASING THREAT OF SHOWERS AND BRING MILDER
TEMPERATURES TO OUR REGION. AS IT MOVES INTO THE UPPER GREAT
LAKES WEDNESDAY SHOWERS WILL BECOME WIDESPREAD AND TEMPERATURES
EVEN MILDER.

&&

.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE IN SE CANADA GRADUALLY BUILDING SOUTH INTO OUR REGION
AND CLOUD COVER SLOWLY ERODING FROM NORTH TO SOUTH...WITH THE
SOUTHERN ADIRONDACKS...LAKE GEORGE SARATOGA REGION...SOUTHERN VT AND
THE BERKSHIRES CLEARING THROUGH THE EARLY MORNING HOURS.  CLOUDS
SHOULD BREAK UP ALONG AND SOUTH OF THE MOHAWK VALLEY INCLUDING THE
CAPITAL DISTRICT THROUGH THIS MORNING...BUT MAY STAY CLOUDY IN THE
SCHOHARIE VALLEY...EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT
INTO THIS AFTERNOON.  SOME BREAK UP OF THE CLOUDS POSSIBLE IN THOSE
AREAS THROUGH THE AFTERNOON.  HOWEVER...MID AND HIGH CLOUDS
ASSOCIATED WITH AN UPPER LEVEL SYSTEM WILL SPREAD ACROSS OUR REGION
MIDDAY THROUGH THIS AFTERNOON. WINDS SHOULD BE LIGHT WITH THE
PROXIMITY TO THE LOW LEVEL RIDGING...SO MIXING WILL BE LIMITED TO
SOME DEGREE. HIGHS TODAY IN THE UPPER 20S TO MID 30S.

UPPER IMPULSE CURRENTLY IN THE OH VALLEY SHOULD BRING SOME
CLOUDINESS TO ALL AREAS THIS AFTERNOON INTO TONIGHT. THERE IS VERY
LITTLE LOW LEVEL MOISTURE ASSOCIATED WITH THE FEATURE BUT THERE ARE
SOME INDICATIONS THAT SOME PATCHY SNOW SHOWER ACTIVITY COULD OCCUR
EAST OF THE HUDSON VALLEY INTO WESTERN NEW ENGLAND WITH A WEAK
SURFACE TROUGH ASSOCIATED WITH THE UPPER ENERGY. INDICATING ISOLATED
SNOW SHOWERS IN THOSE AREAS BUT JUST MOSTLY CLOUDY IN MOST OTHER
AREAS TONIGHT.  LOWS TONIGHT IN THE LOWER TO MID 20S...MID TEENS TO
AROUND 20 IN HIGHER ELEVATIONS.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
MUCH AGREEMENT AMONG THE MDL SUITE (NAM/GFS/ECMWF) DURING THE
PERIOD. ALTHOUGH THE ENTIRE PACKAGE IS SLOWER THAN 12UTC PACKAGE.
THE GEM WAS NOT AVBL.

SUNDAY SFC HIGH PRESSURE COVERS MUCH OF EASTERN NORTH AMERICA WHILE
AT 500HPA GENERALLY A FAST SORTA ZONAL FLOW IS IN PLACE. HWVR THERE
ARE TWO SHORT WVS OVER THE NE USA...AND INVERSIONS REMAIN IN
PLACE RESULTING IN CONSIDERABLE MID AND LOWER CLOUDS. SUN NT THE
500 HPA TROF DEPARTS THE NE WITH SFC HIGH CENTERED FM QB TO ATLC
SEABOARD. WITH MODEST 500HPA RIDGING BUILDING OVER SEABOARD CLOUDS
SHOULD DCR WITH FAIR CONDS.

MONDAY A SERIES OF 500HPA SHORT WVS CARVE A MAJOR FULL LATITUDE
TROF IN THE GRT PLAINS ALONG WITH SFC CYCLOGEN OVER MN/WI.
MEANWHILE FURTHER EAST 500HPA RIDGING ENSUES ALONG THE E
SEABOARD. THIS 500HPA TROF IS WEAKER THAN PVS RUNS DURING THIS
TIME PERIOD. MEANWHILE SFC HIGH ONLY SLOWLY RETREATS OFFSHORE. AS SUCH
WK SE FLOW SETS UP AND MANY AREAS MAY SE SOME SUN PART OF MONDAY.

BUT BY LATE MON AFTN WK ISENTROPIC LIFTS IS DEVELOPING OVER MUCH OF
THE EAST WITH VEERING FLOW W/HT...CSTL FRONT IS SETTING UP ALONG THE
ATLC COAST...AND CLOUDS WILL INCR AND THICKEN. MON INTO TUES NT
500HPA PATTERN BECOMES GREATLY AMPLIFIED WITH SHARPENING RIDGE ALONG
E COAST...AND FULL LAT TROF IN MISS VLY CUTTING OFF. S-SE FLOW
COVERS MUCH OF THE EAST WITH MILDER AIR STREAMING N...HWVR
CSTL/WMFNT REMAINS S OF RGN...AND ISENTROPIC LIFT CONTS TO INCR.

RESULT WILL BE WIDESPREAD CLOUDS AND INCRG CHC OF PCPN. THREAT OF
PCPN WILL ONLY SLOWLY INCR TO SLGT CHC MON NT AND CHC TUE. ANY
PCPN MON NT INTO TUE WILL BE SPOTTY AND LT...--SHSN..ZL...--SHRA. BY
MID MRNG TUES IT SHOULD BE WARM ENOUGH FOR ONLY LIQ PCPN.

THE ECMWF DEVELOPS A SFC WV ALONG THE CSTL FRONT TUES SUG A
HIGHER PROB OF -SHRA MAINLY S PRTNS OF FCA MON NT AND TUE...BUT
AMNTS ARE STILL QUITE LT. TEMPS WILL BE NR NORMALS MON...INCRG TO
10 DEG ABV NORMALS TUES.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
ALL GUID IS POINTING TO A VERY DYNAMIC SYSTEM IMPACTING THE EAST
CHRISTMAS EVE AND DAY...MAKING FOR A VERY BUMPY AND WET RIDE FOR
SANTA.

BY WED MRNG FULL LAT 500HPA TROF IN MISS VLY...AND POWERFUL JET
ROUNDS ITS BASE...DRIVING IT EAST...AND NEGATIVELY TILTING IT. RAPID
CYCLOGEN ENSUES IN OHIO VALLEY...AS LOW DEEPENS AND RACES N INTO
GRTLKS AND CANADA. 500HPA TROF SWINGS EAST AND LLVL JET
INTENSIFIES DRAWING VERY MILD AIR MASS AND RICH ATLC AND GULF
MOISTURE NWRD. SHRA WILL INCR IN COVERAGE AND INTENSITY DURING THE
DAY WED...AS SYSTEMS CDFNT PUSHES E...TO BUF BY EVNG ALB BY 06UTC
AND OFFSHORE BY CHRISTMAS MRNG. CDFNT MAY BE ACCOMP BY HVY FRONTAL
RAIN BAND AND MAYBE ISOLD TSTM. TEMPS WILL INCR DURING THE DAY
WITH HIGHS REACHING NEAR 50. QPF IN ECMWF ON THE ORDER OF 1.5 TO
3.0 INCHES....AND GFS 0.5 TO 2.0 INCHES.

SYSTEM WILL CONTINUE TO MOVE RAPIDLY CHRISTMAS DAY TWRD HUDSON`S
BAY...WITH STRONG CAA INTO FCA ON VERY STRONG NW-W WINDS. TEMPS
WILL PROBABLY FALL DURING THE DAY. LK EFFECT SNOW SHOWERS WILL
DVLP INTO W FCA...AND WITH CUT OFF LIFTING NE...NW FLOW -SHSN OVER
ADRNDKS A GOOD BET.

CHRISTMAS NT THIS SYSTEM RACES N INTO N CANADA AND -SHSN END ACROSS
THE N PRTNS OF RGN. THU NT AND FRI 500HPA RIDGING REASSERTS ITSELF
OVER THE EAST...AS WELL AS AT THE SFC. FRI INTO FRI NT SHOULD
REMAIN FAIR...HWVR ANOTHER STRONG TROF IS MVNG INTO THE GRTLKS FRI
NT...WITH MILDER CONDS AHEAD OF IT...AND POSSIBLE PCPN ARRIVING BY
FRI NT OR SAT.

WHILE THERE ARES SOME TIMING AND PLACEMENT DIFFERENCES BTWN THE GFS
AND ECMWF ON DAY 7 HPC TAKES THE MIDDLE ROAD ON DAY 7. UNTIL DAY
7 ECMWF/GFS IN PRETTY MUCH IN AGREEMENT. WILL POPULATE WITH HPC
FROM MID SHIFT.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM SE ONTARIO THROUGH
THE DAY.A WEAK UPPER IMPULSE WILL TRACK THROUGH THE REGION THIS
AFTERNOON AND EVENING.

MVFR CIGS WILL CONTINUE FROM KALB-KPSF NORTHWARD TO KGFL
THROUGH THE EARLY MORNING HOURS...BEFORE A GRADUAL TREND TOWARD
SCATTERED CLOUDS...ESPECIALLY AT KGFL...BUT KALB COULD SEE SOME
BREAK UP OF THE CLOUDS BY 11Z. AS THE UPPER LEVEL DISTURBANCE
APPROACHES LATER THIS MORNING AND TOWARD MIDDAY...ANY SCATTERED
VARIABLE BROKEN CLOUDS BETWEEN 2500-3500 FEET SHOULD BECOME
PREDOMINANTLY SCATTERED WHILE HIGHER CLOUDS...AROUND 5000-10000
FEET BECOME BROKEN.

NW TO NE WINDS OF 5-10 KTS WILL BECOME LIGHT TO CALM THROUGH
THE EARLY MORNIGN HOURS. EXPECT VERY LIGHT N TO N WINDS OF LESS
THAN 5 KTS IN THE LATE MORNING INTO THE AFTERNOON WITH HIGH
PRESSURE BUILDING IN...BECOMING VARIABLE LESS THAN 5 KT THROUGH
THIS EVENING.

OUTLOOK...

SATURDAY NIGHT TO SUNDAY NIGHT: NO OPERATIONAL IMPACT.  NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF
SHRA...SHSN...FZRA.
TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY RA.
TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
WEDNESDAY: HIGH OPERATIONAL IMPACT. DEFINITE RA.

&&

.HYDROLOGY...
NO HYDROLOGIC ISSUES ANTICIPATED INTO TUESDAY NIGHT. A WIDESPREAD
RAINFALL IS EXPECTED WEDNESDAY/CHRISTMAS AS A LARGE LOW PRESSURE
SYSTEM MOVES ACROSS THE REGION. RAINFALL AMOUNTS OF 1 TO 2 INCHES
ARE LIKELY...WITH POTENTIAL FOR MINOR FLOODING AND SIGNIFICANT
WITHIN BANK RISES OF LARGER STEM RIVERS.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...SNYDER
NEAR TERM...NAS
SHORT TERM...SNYDER
LONG TERM...SNYDER
AVIATION...NAS
HYDROLOGY...SNYDER







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