FXUS61 KALY 112342
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
645 PM EST THU MAR 11 2010
.SYNOPSIS...
A SLOW MOVING STORM SYSTEM WILL INCREASE CLOUDS THROUGHOUT THE
REGION FRIDAY. THIS SYSTEM WILL BRING PRECIPITATION TO THE AREA
FRIDAY NIGHT THROUGH THE WEEKEND...WITH THE HEAVIEST RAIN SOUTH
AND EAST OF THE CAPITAL REGION. DRY WEATHER WILL RETURN EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CLOUDS FINALLY ERODING AWAY...BUT TO BE FOLLOWED LATER ON TONIGHT
WITH MORE STRATUS FROM THE SOUTH. A FEW -SHRA MAY FORM OVERNIGHT
WITH LOW CHC AT BEST IN THE SOUTHEASTERN CATSKILLS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
ON FRIDAY...A LARGE CUTOFF LOW ACROSS THE PLAINS THAT HAS BEEN
SITTING OVER THE REGION FOR A FEW DAYS WILL FINALLY BEGIN TO
SHIFT ITS ENERGY EASTWARD. THE MAIN PRECIP SHIELD TO ENTER
SOUTHERN ZONES FRIDAY NIGHT...SLOW TO PROGRESS
NORTHEASTWARD...WITH BULK OF PRECIP STARTING SATURDAY NIGHT. THE
GFS...NAM...SREF...AND 00Z ECMWF SHOWING NORTHERLY AGEOSTROPHIC
FLOW THROUGHOUT THE SHORT TERM...WHICH SHOULD HELP USHER IN
COLDER...DRYER AIR. THIS WILL DELAY PRECIP INTO SPREADING
NORTHWARD FROM IMPULSES TRAVELING ALONG THE OCCLUDED FRONT OF
THIS SYSTEM. HAVE KEPT LOW CHC POPS IN FA ON FRIDAY...INCREASING
TO LIKELY IN MOSTLY SOUTHERN ZONES FRIDAY NIGHT. WITH RESPECT TO
THE COLDER AIR...925HPA WETBULB TEMPS BELOW FREEZING DURING THE
NIGHT PERIODS..ESPECIALLY OVER THE GREEN MOUNTAINS...PORTIONS OF
THE DACKS AND EVEN THE CATSKILLS. THIS WILL LEAD TO RAIN MIXING
WITH SNOW AND POSSIBLY SOME -FZRA FRIDAY NIGHT AND SATURDAY
NIGHT. 850HPA WETBULB TEMPS STILL ABV FREEZING AND SFC TEMPS COLD
ENOUGH TO SUPPORT -FZRA.
SATURDAY...A SECONDARY LOW WILL FORM NEAR THE DELMARVA
AREA...BRINGING THE HEAVIER PRECIP INTO THE AREA LATE SATURDAY.
GEFS SHOWS 850 HPA U-WIND ANOMALIES OF GREATER THAN 5 STD BELOW
NORMAL ACROSS SOUTHERN NY BY SATURDAY EVENING...WHICH WOULD
SUGGEST A VERY STRONG EASTERLY FLOW ACROSS THE REGION. NAM12 SHOWING
TERRAIN ENHANCEMENT WITH RESPECT AS CAN BE EXPECTED WITH THIS TYPE
OF FLOW...WITH CATSKILLS AND LITCHFIELD HILLS RECEIVING MOST QPF.
INCREASING CLOUDS WILL KEEP MAX TEMPS IN THE 40S FOR FRIDAY AND
SATURDAY AND MIN TEMPS IN THE 30S TONIGHT AND TOMORROW NIGHT.
TOMORROW NIGHT WILL SEE SOME TEMPS BELOW FREEZING IN THE HIGHER
ELEVATIONS. WITH THESE COLDER TEMPERATURES...NOT AS MUCH SNOW MELT
MAY OCCUR AS WAS PREVIOUSLY THOUGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
SATURDAY NIGHT INTO SUNDAY...STILL APPEARS AS IF HEAVIEST QPF
WILL REMAIN JUST S OF REGION...WITH THE EASTERN CATSKILLS...AND
SOUTHERN TACONICS POSSIBLY REACHING 1.5-2.0 FOR STORM TOTAL QPF.
HOWEVER...LEADING EDGE OF BEST U WIND ANOMALIES OF -4 TO -5 SD
/EASTERLY/ OCCUR ACROSS WESTERN CATSKILLS...WITH OUR REGION
REMAINING WITHIN THE LOW LEVEL SPEED DIVERGENT PORTION. ANOTHER
FEATURE WHICH BOTH THE 12Z/11 NAM...GFS...AND MREF INDICATE ARE
COLDER TEMPS WITHIN THE 850-925 MB LAYER THAN RECENT RUNS...AS
SLIGHTLY DRIER AIR GRADUALLY ADVECT SOUTHWEST INTO THE REGION.
MODEL SOUNDINGS HINT AT A PERIOD OF POSSIBLE FREEZING RAIN...OR
EVEN WET SNOW FOR HIGHER ELEVATIONS WITHIN THE
CATSKILLS...DACKS...SOUTHERN GREENS...AND BERKS THROUGH EARLY
SUNDAY AFTERNOON. WE HAVE SIDED WITH THE COLDER MODEL GUIDANCE IN
THESE REGIONS...WHERE SOME MINOR ACCUMS OF SNOW AND/OR ICE ARE
POSSIBLE. ELSEWHERE...MAINLY RAIN IS EXPECTED...ALTHOUGH SOME
SLEET COULD OCCUR EVEN IN THE VALLEYS AT TIMES. EXPECT MAX TEMPS
TO GENERALLY HOLD IN THE 30S FOR HIGHER ELEVATIONS...AND LOWER
40S IN THE VALLEYS.
SUN NT-MON...DEPARTING STORM SYSTEM SHOULD ALLOW FOR STEADIER
PRECIP TO TAPER TO SHOWERS OF RAIN AND SNOW...WITH AREAL COVERAGE
DECREASING FROM N TO S DURING MONDAY. SOME ADDITIONAL...MINOR
SNOWFALL ACCUMS ARE POSSIBLE BEFORE THE PRECIP ENDS...MAINLY FOR
HIGHER ELEVATIONS. OTHERWISE...EXPECT GRADUAL CLEARING TO DEVELOP
FROM N TO S MON AFTERNOON/EVENING. FOR TEMPS...EXPECT SUN NT/MON
AM MINS TO FALL INTO THE 20S FOR HIGHER ELEVATIONS...AND
LOWER/MID 30S FOR VALLEYS...WITH MON MAXES GENERALLY REACHING
45-50...WITH WARMEST MAXES POSSIBLY ACROSS NW AREAS...WHERE
SUNSHINE MAY BREAK THROUGH EARLIER IN THE AFTERNOON.
MON NT-THU...EXPECT GENERALLY FAIR CONDITIONS DURING THIS
PERIOD...ALONG WITH TEMPERATURES NEAR OR ABOVE SEASONAL LEVELS.
THIS SHOULD ALLOW FOR MAXES TO REACH THE LOWER 50S IN THE
VALLEYS...AND 40S FOR HIGHER ELEVATIONS...WITH OVERNIGHT MINS
MAINLY IN THE 20S TO LOWER 30S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
THROUGH THE END OF THE TAF PERIOD (00Z SATURDAY)...EXPECT VFR
CONDITIONS AT KGFL WITH A BKN CLOUD DECK AT AROUND 8000 FEET...
GRADUALLY LOWERING TO AROUND 3500 FEET BY LATE FRIDAY MORNING AND
REMAINING THERE THROUGH FRIDAY AFTERNOON. SURFACE WINDS WILL BE
LIGHT AND VARIABLE...BECOMING EAST AT LESS THAN 10 KTS ON FRIDAY.
AT KALB...BKN VFR CLOUD DECK AT AROUND 8000 FEET WILL GRADUALLY
LOWER TONIGHT...REACHING MVFR LEVELS AT AROUND 3000 FEET AN
INCREASING MARINE INFLUENCE LOWERS THE CLOUD DECK. SURFACE WINDS
WILL BE SOUTHEAST TO EAST AT LESS THAN 10 KTS.
MARINE INCLUENCE ALREADY OCCURRING AT KPOU...SO EXPCET MAINLY MVFR
CIGS THERE THROUGHT HE TAF PERIOD. LATER TONIGHT VSBYS ARE ALSO
LIKELY TO LOWER TO MVFR DUE TO FOG. THE MVFR CIGS AND MAINLY MVFR
VSBYS WILL CONTINU THROUGH FRIDAY...WITH AN INCREASING CHANCE OF
LIGHT RAIN OR SHOWERS LATE IN THE MORNING AND DURING THE AFTERNOON.
SURFACE WINDS WILL BE SOUTHEAST TONIGHT AT LESSTHAN 8 KTS...BECOMING
NORTHEAST ON FRIDAY AT CLOSE TO 10 KTS.
OUTLOOK...
FRI NITE-MON AM...MVFR/IFR...PERIODS OF RA. BREEZY. POTENTIAL FOR
LLWS.
MON PM...VFR...NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THROUGH FRIDAY. A COMPLEX AND
FAIRLY LONG DURATION RAIN EVENT WILL OCCUR BEGINNING FRIDAY NIGHT
CONTINUING THROUGH THE WEEKEND...WITH THE HEAVIEST RAIN EXPECTED
LATE SATURDAY INTO SUNDAY.
CURRENT QPF PROJECTIONS SHOW RAINFALL AMOUNTS WILL RANGE FROM
AROUND A HALF INCH ACROSS THE WESTERN ADIRONDACKS TO AS MUCH AS
TWO INCHES ACROSS WESTERN NEW ENGLAND. SOME ENHANCEMENT OF THE
PRECIPITATION WILL OCCUR IN THE HIGHER TERRAIN OF THE
CATSKILLS...GREEN MOUNTAINS AND BERKSHIRES...ESPECIALLY ON
EASTERN AND SOUTHEASTERN FACING SLOPES...WHERE LOCALLY UP TO
THREE INCHES OF RAIN IS POSSIBLE THROUGH THE ENTIRE EVENT.
IN ADDITION...LATEST NOHRSC IMAGERY SHOWS 4-8 INCHES OF WATER
EQUIVALENT REMAINS IN THE SNOWPACK ACROSS THE
CATSKILLS...ADIRONDACKS...GREENS...AND BERKSHIRES...WITH THE
HIGHEST VALUES IN THE CATSKILLS AND SOUTHERN GREENS.
THIS EXPECTED RAINFALL...ALONG WITH SOME SNOW MELT DUE TO A
PERIOD OF TEMPERATURES OVER 40 DEGREES...WILL LIKELY CAUSE SOME
FLOODING ON RIVERS AND STREAMS BY SUNDAY AND POSSIBLY INTO EARLY
NEXT WEEK...MAINLY FOR AREAS SOUTH AND EAST OF THE CAPITAL
REGION. THE TREND IS SLIGHTLY SLOWER WIT THE RAIN AND SLIGHTLY
COLDER WITH POSSIBLE MIXED PRECIPITATION IN THE MOUNTAINS. STILL
TOO EARLY TO HOIST ANY FLOOD WATCHES BUT MIGHT DO SO BY FRIDAY
AFTERNOON.
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...KGS
NEAR TERM...KGS
SHORT TERM...KGS
LONG TERM...KL
AVIATION...GJM
HYDROLOGY...HWJIV
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