FXUS61 KALY 030528
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1227 AM EST THU DEC 3 2009
.SYNOPSIS...
A STRONG LOW PRESSURE SYSTEM WILL TRACK FROM THE OHIO VALLEY TO THE
EASTERN GREAT LAKES REGION TONIGHT INTO THURSDAY MORNING...BEFORE
LIFTING NORTHEAST INTO NORTHERN NEW ENGLAND AND THE CANADIAN
MARITIMES BY LATE THURSDAY. THIS SYSTEM WILL BRING A WIDESPREAD
SOAKING RAINFALL TO THE REGION...AS WELL AS GUSTY WINDS.
TEMPERATURES WILL BE VERY MILD ON THURSDAY BEFORE COLDER AIR MOVES
IN BEHIND THE LOW PRESSURE SYSTEM. A COLDER AND DRIER AIR MASS WILL
REMAIN IN PLACE FOR THE END OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
CURRENT EVOLUTION OF SYSTEM AND ASSOCIATED PRECIPITATION SHIELD
CONSISTENT WITH CURRENT FORECAST. SOME TEMPERATURES ARE A COUPLE
OF DEGREES FROM FORECASTED MINIMA...SO JUST A FEW MINOR
TEMPERATURE ADJUSTMENTS. OTHERWISE...RAIN CONTINUES TO SPREAD
ACROSS THE REGION...AND THERE MAY BE AN ISOLATED RUMBLE OF THUNDER
TOWARD SUNRISE. WINDS WILL INCREASE AND BECOME QUITE GUSTY BY
SUNRISE...BUT NO WIDESPREAD GUSTS ABOVE 45 MPH EXPECTED MATE
TONIGHT OR TOMORROW...BUT SOME OF THE HIGHER ELEVATIONS MAY SEE
SOME HIGHER GUSTS. WIND GUSTS OVER 40 MPH CAN KNOCK DOWN SOME
ISOLATED TREES AND BRANCHES...BUT AGAIN...NOT EXPECTED TO BE
WIDESPREAD ENOUGH FOR ANY WIND HEADLINES. NO OTHER CHANGES.
PREV AFD BELOW...
AS OF 315 PM...HIGH LEVEL CLOUDS CURRENTLY INCREASING FROM THE SOUTH
AS A POTENT LOW PRESSURE SYSTEM OVER KENTUCKY/TENNESSEE STARTS TO
LIFT NORTHWARD. VIGOROUS 500 MB CLOSED LOW IS FORECAST TO OPEN UP
TONIGHT AND ACCELERATE AS IT TRACKS INTO THE OHIO VALLEY. RAIN
SHIELD MAKING PROGRESS BUT CONFINED TO SOUTHERN PA/NJ AT THIS HOUR.
IT WILL TAKE SEVERAL MORE HOURS FOR THE RAIN TO BEGIN ACROSS OUR
SOUTHERN ZONES. WILL MENTION DRY CONDITIONS INTO THE EVENING...THEN
RAPIDLY INCREASE POPS FROM SOUTH TO NORTH BY MID TO LATE EVENING.
TEMP PROFILES WILL BE WARM ENOUGH FOR AN ALL RAIN EVENT ACROSS THE
ENTIRE FORECAST AREA DESPITE BEING EARLY DECEMBER. A SOAKING
RAINFALL IS LIKELY ACROSS THE AREA WITH GENERALLY 0.75 TO 1.50
INCHES EXPECTED.
THERE ARE SOME DIFFERENCES IN FORECAST MODELS WITH REGARDS TO THE
EXACT TRACK OF THE SFC LOW CENTER...HOWEVER REGARDLESS OF THE EXACT
TRACK WHICH WILL BE WEST OF THE AREA...PTYPE IS NOT AN ISSUE AND
WILL BE ALL RAIN. THERE ARE SOME QPF DIFFERENCES...WITH ONE
NOTICEABLE OUTLIER BEING THE 12Z GFS. THE GFS PUTS THE HIGHEST QPF
OF 1.50-2.00 INCHES ACROSS THE SOUTHERN ADIRONDACKS WITH LESS THAN
0.75 INCHES SOUTH AND EAST OF THERE. THIS DOES NOT SEEM AS
REASONABLE...SINCE MORE SIGNIFICANT RAINFALL SHOULD OCCUR ALONG THE
NOSE OF THE SOUTHEAST LOW LEVEL JET AXIS...WHICH WILL BE ACROSS
SOUTHEAST AREAS. SO...WILL GO WITH A UNIFORM QPF SOLUTION MORE IN
LINE WITH 12Z ECMWF/GGEM INDICATING A PROGRESSIVE TRACK WHICH SHOULD
PRECLUDE SIGNIFICANT PRECIP. PLEASE REFER TO HYDRO SECTION FOR
FURTHER DETAILS.
THERE WILL ALSO BE SOME WIND ISSUED TO DEAL WITH FOR THIS SYSTEM
BOTH PRIOR TO AND AFTER LOW PRESSURE MOVES THROUGH.
FIRST...INCREASING SOUTHEAST FLOW ALOFT TO AROUND 60-70 KT WILL
OCCUR OVERNIGHT MAINLY ACROSS SOUTHEAST AREAS. HOWEVER...WITH AN
INVERSION FORECAST TO BE IN PLACE IT WILL BE DIFFICULT FOR THESE
STRONG WINDS TO MID TO THE GROUND. STILL...SOME 35 TO 45 MPH GUSTS
ARE POSSIBLE IN THE TYPICALLY FAVORED AREAS FOR CHANNELING IN
SOUTHEAST FLOW SUCH AS THE SOUTHERN GREEN MOUNTAINS...NORTHERN
BERKSHIRES AND THE HIGHEST ELEVATIONS OF THE EASTERN CATSKILLS. THE
MORE SUBSTANTIAL 925 MB WINDS ARE FORECAST ALONG COASTAL AREAS...SO
WINDS WILL NOT BE MUCH OF A CONCERN ELSEWHERE THROUGH AROUND 12Z.
MODELS INDICATING SOME ELEVATED INSTABILITY PRESENT FROM AROUND
09Z-12Z SO WILL MENTION A CHANCE OF THUNDER. IT DOES NOT APPEAR
THERE WILL BE ANY SURFACE BASED INSTABILITY AND ANY LINEAR FORCED
CONVECTIVE LINES SHOULD OCCUR SOUTH AND EAST OF OUR AREA.
MIN TEMPS WILL OCCUR MAINLY THROUGH MIDNIGHT...THEN GRADUALLY RISE
THEREAFTER.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 330 PM...BY AROUND 12Z-15Z THUR THE RAINFALL WILL BE TAPERING
OFF FROM SOUTHWEST TO NORTHEAST ACROSS THE AREA AS THE LOW PULLS
AWAY INTO NORTHERN NEW ENGLAND. WINDS WILL SHIFT TO THE
SOUTHWEST...AS THE STRONGEST CORE OF WINDS ALOFT SHIFTS WELL TO THE
EAST OF THE REGION. STILL...THERE WILL BE MUCH BETTER POTENTIAL FOR
MIXING TO OCCUR WITH BREAKS OF SUN DEVELOPING BY AFTERNOON AND
WEST-SOUTHWEST WINDS COULD GUSTS BETWEEN 35-40 MPH AT TIMES. AS A
RESULT IN SOME SUNSHINE AND STRONG MIXING FOR THIS TIME OF
YEAR...TEMPS WILL RISE INTO THE UPPER 50S TO LOWER 60S FROM THE
CAPITAL REGION SOUTH AND EAST. THE RECORD HIGH FOR ALBANY IS 58 AND
THAT RECORD COULD BE BROKEN. PLEASE REFER TO CLIMO SECTION FOR
DETAILS.
DRIER AND COLDER AIR WILL GRADUALLY FILTER INTO THE REGION THUR
NIGHT AS A COLD ADVECTION REGIME SETS IN. THERE WILL BE ISOLATED TO
SCATTERED LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN ADIRONDACKS
THUR NIGHT THROUGH FRI NIGHT...HOWEVER RELATIVELY LOW INVERSION
HEIGHTS AND MARGINAL LAKE-INDUCED INSTABILITY WILL PRECLUDE A
SIGNIFICANT EVENT. WILL MENTION MAINLY CHANCE POPS FOR NOW...WITH
POTENTIAL REFINEMENT WITH SUBSEQUENT FORECASTS. WITH A W-SW MIXED
LAYER FLOW REGIME FRI INTO FRI NIGHT...SNOW SHOWERS SHOULD BE
CONFINED TO NORTHERN PORTIONS OF THE WESTERN ADIRONDACKS WITH ONLY
MINOR ACCUMULATIONS EXPECTED AT THIS TIME. TEMPS WILL BE CLOSER TO
SEASONAL AVERAGES THROUGH FRI NIGHT...BUT WILL BE SLIGHTLY ABOVE
NORMAL.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
EXCEPT FOR A SLIGHT TO LOW CHANCE FOR SNOW SHOWERS OVER THE WEST
AND NORTHWEST PART OF THE FORECAST AREA DUE TO A WEAK LAKE EFFECT
PATTERN OR WEAK WARM ADVECTION....EXPECT FAIR AND SEASONABLY COLD
WEATHER FOR MOST OF THE FORECAST AREA SATURDAY THROUGH TUESDAY. THE
SURFACE WAVE MOVING OFF THE SOUTHEAST COAST ON SATURDAY WILL LIKELY
PASS OUT TO SEA WELL TO OUR SOUTH AND EAST...WITH LITTLE IF ANY
IMPACT ON OUR FORECAST AREA. AFTER THAT...A LARGE HIGH PRESSURE AREA
WILL BUILD INTO THE REGION AND DOMINATE THROUGH TUESDAY. TEMPS WILL
BE FAIRLY UNIFORM SATURDAY THROUGH TUESDAY WITH HIGHS GENERALLY
BETWEEN 30 AND 40...AND THE LOWS IN THE UPPER TEENS TO MID 20S.
THE NEXT SYSTEM THAT MAY BRING ANY WIDESPREAD PCPN TO THE REGION
WILL NOT OCCUR UNTIL TUESDAY NIGHT AND WEDNESDAY. RIGHT NOW THE GFS
AND ECMWF DIFFER CONSIDERABLY. THE GFS IS MUCH STRONGER WITH MUCH
MORE SIGNIFICANT QPF. THE ECMWF HAS A WEAK SYSTEM WITH SPOTTY PCPN
DURING THIS PERIOD. AT THIS POINT WILL COMPROMISE ON A 40 PERCENT
CHANCE OF PCPN ON WEDNESDAY.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
LESS THAN IDEAL AVIATION CONDITIONS OVERNIGHT WITH THE COMBINATION
OF MVFR/IFR CIG AND VIS AND LLWS. VWP FROM THE RADARS REVEAL
INCREASING LLJ WITH NEAR 50KTS AT 2K FEET. THIS WILL CONTINUE THE
REMAINDER OF THE OVERNIGHT HOURS AND HAVE HIT THIS HARD IN THE
TAFS. CHANCES OF THIS HIGHER MOMENTUM AIR REACHING THE GROUND IS
RATHER LOW AND WILL ONLY PLACE WIND GUSTS INTO THE 20KT RANGE AS
SOUTHERLY FLOW MOVES UP THE HUDSON RIVER VALLEY.
AS THIS STORM QUICKLY TRACKS AWAY FROM THE REGION...DRY SLOT AND
INCREASED MIXING WITHIN THE TIGHT PRESSURE GRADIENT WILL RESULT IN
BETTER POTENTIAL FOR THE HIGHER MOMENTUM AIR TO REACH THE GROUND
WITH 30KTS EXPECTED UNDER A SCT-BKN MVFR CLOUD DECK.
OUTLOOK...
THU OVRNT-SUN...VFR...NO SIG WX.
MON...VFR TO MVFR...CHANCE -SN.
&&
.HYDROLOGY...
A LOW PRESSURE SYSTEM APPROACHING FROM THE OHIO VALLEY WILL BRING A
WIDESPREAD RAINFALL...WITH TOTAL QPF AROUND 0.75 TO 1.50 INCHES
LIKELY FROM TONIGHT INTO THURSDAY MORNING. THIS RAINFALL WILL CAUSE
SIGNIFICANT RISES ON AREA RIVERS...BUT WILL LIKELY REMAIN WITHIN
THEIR BANKS.
MODELS INDICATE THAT THE BULK OF THE RAIN WILL OCCUR BETWEEN
MIDNIGHT AND 7 AM THURSDAY. THIS HIGH INTENSITY RAINFALL MAY CAUSE
SOME SMALL STREAMS TO FLOOD EARLY THURSDAY...AND WITH FALLEN LEAVES
STILL AROUND MAY ALSO RESULT IN SOME DRAINAGE PROBLEMS ON ROADS AND
PARKING AREAS. AN EMBEDDED THUNDERSTORM OR TWO IS POSSIBLE WHICH
COULD LOCALLY ENHANCE RAINFALL AMOUNTS. RAIN WILL END THURSDAY
MORNING AND THE STORM SYSTEM PULLS AWAY. BREEZY CONDITIONS WILL
FOLLOW.
SOME LIGHT LAKE EFFECT SNOW MAY OCCUR THURSDAY NIGHT AND FRIDAY
ACROSS PORTIONS OF THE WESTERN ADIRONDACKS IN THE WAKE OF THE STORM
AS COLDER AIR MOVES BACK IN...BUT OTHERWISE IT WILL BE DRY ACROSS
MUCH OF THE AREA. MAINLY DRY WEATHER IS EXPECTED THE REMAINDER OF
THE PERIOD INTO THE WEEKEND...WITH JUST A CHANCE OF SOME LIGHT SNOW
FROM THE FRINGES OF AN OCEAN LOW MOVING WELL OFF SHORE.
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.
&&
.CLIMATE...
TEMPERATURES ON THURSDAY ARE FORECAST TO EXCEED DAILY HIGH
TEMPERATURES RECORDS. BELOW IS A CHART OF THE OLD RECORDS...THE YEAR
THEY WERE SET...AND THE FORECAST HIGH TEMP FOR DECEMBER 3RD.
LOCATION RECORD YEAR FORECAST HIGH
ALBANY 58 1998 59
POUGHKEEPSIE 58 1962 63
GLENS FALLS 55 1998 57
PITTSFIELD 57 1950 59
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
AVIATION...BGM
WWW.WEATHER.GOV/ALBANY
