FXUS61 KALY 272138
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
438 PM EST FRI NOV 27 2009
.SYNOPSIS...
LOW PRESSURE STRENGTHENING NORTHEAST OF CAPE COD TONIGHT...WILL MOVE
SLOWLY ALONG THE COAST OF MAINE LATER TONIGHT AND SATURDAY. THIS
STORM WILL IMPACT THE NORTHEAST WITH UNSETTLED WEATHER INCLUDING
RAIN...SOME SNOW ACROSS THE HIGHER ELEVATIONS...AND STRONG GUSTY
WINDS. THE STORM WILL MOVE INTO THE CANADIAN MARITIMES BY
SUNDAY...WITH HIGH PRESSURE BUILDING IN FROM THE SOUTHWEST. &&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
27/21Z RUC ANALYSIS SHOWS 981MB LOW PRESSURE 120 MILES NE OF CAPE
COD. SYSTEM IS FORECAST TO CONTINUE DEEPENING THROUGH THIS EVENING
WITH A SLOW NNE MOVEMENT. HEAVIEST PRECIPITATION WITH WARM
CONVEYOR BELT NORTH AND EAST OF ALBANY FORECAST AREA...AND
FORECAST TO REMAIN THERE THROUGH EARLY EVENING. RADAR SHOWS NARROW
BANDS OF LIGHT PRECIPITATION ORIENTED NORTHWEST TO SOUTHEAST
ACROSS THE AREA. AUTOMATED TEMPERATURE SENSORS SHOW FREEZING LEVEL
CURRENTLY AROUND 1500FT MSL WEST TO 2000FT MSL EAST. LIGHT RAIN
SHOWERS OCCURRING IN THE VALLEYS WITH SNOW AT HIGHER ELEVATIONS.
WEB CAMS AT SKI AREAS WHERE PRECIPITATION IS FALLING CONFIRM
THIS...SHOWING LIGHT SNOW ACCUMULATIONS.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH SUNDAY NIGHT/...
TWO AREAS OF CONCERN FOR NEXT 24 HOURS...ONE BEING SNOWFALL
ACCUMULATIONS OVER SOUTHERN VERMONT AND NORTHERN BERKSHIRE COUNTY
OVERNIGHT. THE OTHER WILL BE STRONG GUSTY WINDS TONIGHT AND
SATURDAY MORNING.
12Z MODELS IN AGREEMENT SHOWING NORTH/SOUTH BAND OF DEFORMATION
PRECIPITATION DEVELOPING EAST OF HUDSON VALLEY OVERNIGHT...AS LOW
PRESSURE DEEPENS AND ONLY SLOWLY PULLS AWAY. 12Z/NAM HAD HEAVIEST
PRECIPITATION FORECAST...WITH AROUND AN INCH OF LIQUID EQUIVALENT
OVER SOUTHERN VERMONT OVERNIGHT. 12Z/GFS HAS HALF AS MUCH...AND
18Z/NAM NOW SHOWS HALF INCH OR LESS LIQUID. EVEN IF A MAJORITY OF
THIS PRECIPITATION WERE TO FALL AS SNOW...SNOWFALL AMOUNTS LOOK TO
BE BELOW ADVISORY THRESHOLDS...1 TO 3 INCHES...BUT TRAVEL MAY BECOME
DIFFICULT OVER THE HIGHER TERRAIN OF SOUTHERN VERMONT LATER
TONIGHT DUE TO BLOWING AND DRIFTING SNOW.
WIND ADVISORY/WIND WARNINGS REMAIN IN EFFECT FROM 6PM TONIGHT
UNTIL 6 PM SATURDAY. LATEST PEAK WIND REPORTS SHOW 30MPH AT
KALB...32MPH ON THE ROOF HERE AT THE OFFICE...3OMPH AT KPOU AND
20MPH AT MARLBORO VERMONT. LATEST MODEL RUNS SHOW WINDS A LITTLE
LOWER THAN PREVIOUS FORECASTS SO KNOCKED FORECAST PEAK WINDS DOWN
ABOUT 10MPH ACROSS THE HIGHER TERRAIN DURING WARNING/ADVISORY PERIOD.
ON SATURDAY...850MB CONVERGENCE COUPLED WITH LOW LEVEL MOISTURE ADVECTION
FROM GREAT LAKES AND UPSLOPE FLOW WILL LIKELY KEEP HIGHER TERRAIN
MOSTLY CLOUDY...WITH A FEW LIGHT SNOW SHOWERS. VALLEYS WILL SEE
BREAKS OF SUN. AS LOW PULLS AWAY SATURDAY...PRESSURE GRADIENT SLACKENS
AND WINDS SHOULD DIMINISH RAPIDLY AFTER SUNSET. SATURDAY NIGHT
FLOW REMAINS NORTHWEST...SO CLOUDS WILL LINGER NORTH AND WEST. ON
SUNDAY...WINDS BACK TOWARDS SOUTHWEST AND WEAK WARM ADVECTION IS
EXPECTED. CLOUDS SHOULD BREAK ACROSS MOST OF THE AREA AND
TEMPERATURES SHOULD MODERATE. MID HUDSON VALLEY LOCATIONS MAY
TOUCH 50F. STAYED CLOSE TO MAV MOS TEMPERATURE GUIDANCE THROUGH
SHORT TERM PERIOD.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
CONSENSUS IS TO GO WITH HPC GUIDANCE TODAY...AS THE HPC OPINION IS
THAT GFS IS TOO QUICKLY AND TOO FAR OUT TO SEA WITH THE STORM LATE
NEXT WEEK. THEY SUPPORT MORE THE ECMWF APPROACH...WHICH TRACKS THE
LOW ROUGHLY UP ALONG THE APPALACHIANS.
IN THE MEANTIME...FOR MONDAY...A COLD FRONT SLIDES ACROSS OUR
FORECAST AREA SOMETIME DURING THE DAY. THIS TIME...HPC AGREES MORE
WITH GFS'S TIMING...WHILE THE ECMWF HAS IT THROUGH SOMETIME AROUND
DAYBREAK. BOTH THE GFS AND ECMWF GIVE QPFS IN THE QUARTER TO A
THIRD OF AN INCH BALLPARK...WHICH IS HOW WE POPULATED. THIS WILL BE
MAINLY RAIN SHOWERS IN THE SOUTH AND VALLEYS...WITH SNOW SHOWERS OR
A MIX AT HIGHER ELEVATIONS...MAINLY IN THE ADIRONDACKS AND HIGH
PEAKS OF THE GREENS. THINGS BEGIN TO WIND DOWN MONDAY NIGHT...AND
THE EMPHASIS SHIFTS TO THE WESTERN PORTIONS OF THE ADIRONDACKS AND
MOHAWK VALLEY...WHERE WESTERLY WINDS BEHIND THE FRONT...AND A LAKE
ENHANCED TROF...WILL LIKELY PROVIDE AN INCH OR TWO IN SNOW SHOWERS.
TUESDAY NIGHT INTO WEDNESDAY WILL BE QUIET...BUT THE NEXT SYSTEM...
OUT OF THE GULF OF MEXICO...SPINS UP AND TRACKS QUICKLY UP THE
APPALACHIANS. WE SPIN UP THE POPS TO CHC IN THE WEST WEDNESDAY...
BUT THE STORM WILL MORE LIKELY NOT BEGIN TO DUMP ITS CONTENTS UNTIL
THE OVERNIGHT PERIOD. ECMWF HAS THICKNESSES RISING WELL BEYOND 540
BY EARLY TUESDAY. THE GFS HEIGHTS WITH THE 540 LINE AS FAR NORTH AS
OUR NORTHERN ZONES SEEMS FAR MORE REALISTIC. THIS WILL BE A MIXED
EVENT WHICH WILL NEED CLOSE MONITORING. THE ECMWF PROVIDES FAR
HIGHER QPFS THAN THE GFS ATTM. WE HAVE CHC POPS WED NGT THRU THU
WHEN THE STORM WILL BE PASSING THROUGH NEW YORK STATE. A MORE
WESTERLY WIND FLOW BRINGS A CHC FOR SOME MEASURABLE LAKE EFFECT
SNOW SHOWERS ON FRIDAY...MAINLY AGAIN FOR THE WESTERN ADIRONDACKS
AND MOHAWK VALLEY.
TEMPERATURES TAKE ABOUT A 10 DEGREE DROP BEHIND THE COLD FRONT
MONDAY INTO TUESDAY. MOST HIGHS TUESDAY WILL BE IN ONLY THE
30S...WITH OVERNIGHT LOWS TUESDAY NIGHT IN THE UPPER TEENS AND THE
20S. BUT TEMPERATURES BOUNCE BACK TO MONDAY'S LEVELS AND BEYOND BY
THURSDAY AS THE ENCROACHING LOW PASSES JUST TO OUR WEST AND DRAWS IN
MILDER AIR ON SOUTHEASTERLY WINDS...ENOUGH TO FAVOR A MIXED EVENT
OVER A SNOW EVENT. THEN IT'S BACK TO HIGHS IN THE 30S FOR FRIDAY.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
LOW PRESSURE CONTINUES TO DEEPEN AND INTENSIFY NEAR THE GULF OF
MAINE THIS AFTERNOON. CIGS/VSBYS WILL CONTINUE TO BE IN THE LOW
VFR/MVFR RANGE INTO THE OVERNIGHT PERIOD. SHOWERS WILL TRANSITION
TO SNOW SHOWERS OUTSIDE OF THE HUDSON RIVER VALLEY OVERNIGHT. THE
BIGGER ISSUES FOR THE TERMINALS OVERNIGHT THRU TOMORROW MORNING WILL
BE THE WINDS.
EXPECT VFR CONDITIONS TO PREVAIL AFTER 06Z AT KPOU/KALB/KGFL...BUT
THE WINDS WILL INCREASE FROM THE W/NW AT 10-15 KTS TO 15-24 KTS
WITH SOME GUSTS IN THE 35-40 KT RANGE. THE STRONG WINDS ARE DUE TO
THE TIGHT LOW LEVEL SFC PRESSURE GRADIENT BETWEEN THE INTENSE
CYCLONE MOVING INTO THE CANADIAN MARITIMES...AND HIGH PRESSURE
OVER THE SOUTHEASTERN US. THE STRONGER GUSTS IN THE 35-40 KT RANGE
WILL BE DUE TO THE MOMENTUM TRANSFER FROM 925 HPA OR 2-2.5 KFT
AGL. THE WINDS WILL BEGIN TO SUBSIDE AFTER 1700 UTC WITH THE SFC
PRESSURE GRADIENT STARTING TO WEAKEN.
OUTLOOK...
SUN...VFR. NO SIG WX.
SUN NT-MON...MVFR/IFR. -RA/-SN.
TUE...VFR. SLGT CHC -SHRA/-SHSN.
WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
PRECIPITATION GAGES SHOW THAT RAINFALL HAS BEEN AROUND A HALF
INCH OR LESS ACROSS OUR HYDROLOGIC SERVICE AREA...WITH THE
HEAVIEST PRECIPITATION FALLING IN A BAND FROM EASTERN LITCHFIELD
COUNTY CONNECTICUT THROUGH BERKSHIRE COUNTY MASSACHUSETTS INTO
WINDHAM COUNTY VERMONT. RIVER RISES IN THESE AREAS ARE FORECAST TO
BE AROUND A FOOT. ELSEWHERE..RISES ARE FORECAST TO BE LESS THAN A
FOOT.
NORTHERN BERKSHIRE COUNTY MASS AND SOUTHERN VERMONT MAY RECEIVE
ANOTHER HALF INCH OF LIQUID EQUIVALENT PRECIPITATION TONIGHT...MAINLY
AS SNOW. THE NEXT CHANCE FOR SIGNIFICANT PRECIPITATION WILL BE ON
MONDAY. LIQUID EQUIVALENT PRECIPITATION IS EXPECTED TO BE A HALF
INCH OR LESS. SOME MODERATE RISES MAY OCCUR ON RIVERS IN SOUTHERN
VERMONT ON MONDAY DUE TO A COMBINATION OF SNOWMELT AND RAINFALL.
ELSEWHERE...MINOR CHANGES IN RIVER ELEVATIONS ARE EXPECTED OUTSIDE
OF LOCATIONS AFFECTED BY POWER GENERATION OR DIVERSIONS.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...WIND ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST SATURDAY FOR
CTZ001-013.
NY...HIGH WIND WARNING FROM 6 PM THIS EVENING TO 6 PM EST SATURDAY
FOR NYZ033-042-047-051-058-063-082.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST SATURDAY FOR
NYZ032-038>041-043-048>050-052>054-059>061-064>066-083-
084.
MA...HIGH WIND WARNING FROM 6 PM THIS EVENING TO 6 PM EST SATURDAY
FOR MAZ001-025.
VT...HIGH WIND WARNING FROM 6 PM THIS EVENING TO 6 PM EST SATURDAY
FOR VTZ013-014.
WIND ADVISORY FROM 6 PM THIS EVENING TO 6 PM EST SATURDAY FOR
VTZ015.
&&
$$
SYNOPSIS...SND
NEAR TERM...SND
SHORT TERM...SND
LONG TERM...ELH
AVIATION...WASULA
HYDROLOGY...SND
