FXUS61 KALY 240232 RRA
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
932 PM EST WED DEC 23 2009
.SYNOPSIS...
HIGH PRESSURE FROM CANADA WILL BUILD INTO THE REGION LATE TONIGHT
AND FRIDAY. A STRONG LOW PRESSURE SYSTEM WILL MOVE NORTH FROM THE
SOUTHERN PLAINS TOWARD THE WESTERN GREAT LAKES LATER IN THE WEEK AS
A FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW MOVES INTO OUR REGION
LATE FRIDAY NIGHT AND SATURDAY. ANOTHER AREA OF LOW PRESSURE IS
EXPECTED TO DEVELOP ALONG THIS BOUNDARY ON SATURDAY. THIS SCENARIO
WILL LIKELY BRING MIXED PRECIPITATION TO THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 900 PM RADAR RETURNS AND SURFACE INDICATE NOTHING MORE THAN
FLURRIES REMAIN ACROSS THE REGION...SO WILL FORECAST OCASIONAL
FLURRIES FOR THE REST OF TONIGHT. HAVE INCREASED THE CLOUD COVER
FROM THE PREVIOUS FORECAST...AND HAVE ALSO TWEAKED OVERNIGHT LOWS
DOWN ALITTLE IN A FEW AREAS...OTHERWISE THE PREVIOUS FORECAST IS
UNCHANGED.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
TRANQUIL WEATHER WILL PREVAIL ON THURSDAY AND THURSDAY NIGHT. THE
ONLY REAL CHALLENGE IS HOW MUCH CLOUD COVER WILL LINGER. MODEL
SOUNDINGS SUGGEST A PRETTY HEFTY LOW INVERSION WHICH COULD SERVE TO
TRAP MOISTURE UNDERNEATH IT. IF THIS HAPPENS...CLOUDS WILL PREVAIL.
HOWEVER...THERE IS ALSO A CHANCE THAT ENOUGH DRYING DUE TO
SUBSIDENCE COULD DRY THE MOISTURE. FOR NOW...WILL PLAY IN
BETWEEN...CALLING IT PARTLY CLOUDY BOTH THURSDAY AND THURSDAY NIGHT.
CLOUDS OR NOT...TEMPERATURES ON THURSDAY WILL BE LESS COLD THAN
PREVIOUS DAYS. WE ARE FORECASTING A HIGH TEMPERATURE OF 33 DEGREES
FOR ALBANY. IF THIS HAPPENS...IT WOULD BE THE FIRST TIME SINCE
DECEMBER 15TH WE HAVE CRACKED THE FREEZING MARK! OVERALL LOOK FOR
HIGHS GENERALLY IN THE 30S REGION WIDE. WITH SOME PATCHY CLOUDS
AROUND AND SOME WARMING ALOFT...WE DON'T THINK TEMPERATURES WILL
DROP TOO PRECIPITOUSLY ON THURSDAY NIGHT. HOWEVER...IF WE WERE TO
COMPLETELY CLEAR...TEMPERATURES COULD DROP A BIT COLDER THAN WE OUR
CURRENTLY FORECASTING...AS THE WIND WILL GO NEARLY CALM. EITHER
WAY...IT WILL REMAIN DRY. RIGHT NOW...FIGURE ON LOW TEMPERATES FROM
THE TEENS NORTH...LOWER 20S SOUTH.
FOR FRIDAY...THE WEATHER WILL REMAIN DRY. THE ONLY POSSIBLE
EXCEPTION MIGHT BE A FEW SNOW SHOWERS MAKING IT INTO THE CATSKILLS
BY LATE IN THE DAY...BUT THE LION SHARE OF THE NEXT IMPENDING STORM
WILL STAY JUST TO OUR WEST. TEMPERATURES ONCE AGAIN WILL BE
SEASONABLE...IN THE 30S...TO NEAR 40 IN SOME OF THE "WARMER" SPOTS.
ACTUALLY...IF THE 18Z NAM IS CORRECT...PRECIPITATION MIGHT NOT REACH
THE HUDSON VALLEY UNTIL SATURDAY NIGHT. HOWEVER...THE 12Z
CANADIAN/EUROPEAN AND GFS MODELS INDICATE IT WILL REACH ALL OF OUR
AREA BY 12Z SATURDAY. THE STRONG RIDGE THAT HAS BEEN RESIDING OVER
GREENLAND (CALLED THE GREENLAND BLOCK) IS STILL FORECAST TO
RETROGRADE EASTWARD INTO EASTERN CANADA AND COULD VERY PREVENT
PRECIPITATION FROM THE NEXT STORM...TO REMAIN TO OUR WEST INITIALLY.
TIMING THIS FAR OUT IS TOO UNCERTAINTY SO FOR NOW...WILL LEAN WITH
THE SOMEWHAT FASTER ONSET.
GIVEN THIS THINKING...PRECIPITATION...IN THE FORM OF SNOW AND SLEET
WOULD OVERSPREAD OUR REGION FRIDAY NIGHT. BY SATURDAY...AS THE MAIN
STORM INITIALLY LIFTS WAY TO OUR NORTHWEST INTO THE GREAT LAKES
REGION POUNDING THAT REGION WITH ANOTHER SIGNIFICANT WINTER STORM
CLOSER TO HOME...A SECONDARY LOW IS FORECAST TO FORM ALONG THE
TRIPLE POINT...OVER VIRGINIA. THIS SCENARIO WOULD SERVE TO PREVENT
THE REALLY MILD AIR...STREAMING IN FROM THE SOUTHEAST...FROM EVER
REACHING OUR REGION. WARMER AIR HOWEVER WILL "NOSE" IN
ALOFT...CHANGING ANY SNOW OR SLEET TO FREEZING RAIN OR RAIN. RIGHT
NOW...THIS DOES NOT APPEAR TO BE A CLASSIC ICE STORM SET UP...AS THE
SURFACE HIGH REMAIN TO OUR NORTHEAST (AS OPPOSED TO NORTH) WHICH
SHOULD ALLOW ENOUGH WARM AIR TO BRING ABOVE FREEZING TEMPERATURES TO
MOST AREA DURING SATURDAY. STILL...SOME ICING LOOKS POSSIBLE ALONG
WITH MINOR OR PERHAPS MODERATE ACCUMULATIONS OF SNOW AND SLEET
(MAINLY NORTH). THE OTHER CONCERN WITH THIS STORM IS HOW MUCH RAIN
WILL FALL. RIGHT NOW THE 12Z MREFS INDICATE A LITTLE LESS THAN AN
INCH FOR ALBANY...A LITTLE MORE FURTHER SOUTH. THIS IS A BIT LESS
THAN THE PREVIOUS RUN. THE EUROPEAN MODEL HAS ALSO BACKED OFF QPF
AMOUNTS A BIT...AT LEAST FOR THE TIME BEING.
LOOK FOR HIGH TEMPERATURES IN THE 30S TO NEAR 40 SOUTH ON
SATURDAY...AND ONLY DROPPING A LITTLE BACK DOWN AROUND FREEZING MARK
BY SUNDAY MORNING.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ON SUNDAY NIGHT INTO MONDAY...SOME SNOW SHOWERS ARE POSSIBLE AS THE
LARGE CUTOFF UPPER LEVEL LOW RESPONSIBLE FOR THE WEEKEND SFC SYSTEM
WILL BE SLOWLY MAKING PROGRESS ACROSS THE REGION. THE 12 UTC GFS AND
ECMWF ARE STILL NOT IN AGREEMENT...AS THE GFS HAS THE UPPER LOW
BASICALLY RIGHT OVER UPSTATE NY BY SUN NIGHT ...WHILE THE ECMWF IS
SLOWER AND STILL LAGS THE SYSTEM BACK ACROSS THE OHIO VALLEY AND
EVENTUALLY ACROSS SOUTHERN PARTS OF THE REGION BY MONDAY EVENING.
WITH LIMITED MOISTURE REMAINING ACROSS THE AREA...THE BEST CHC OF
SEEING SNOW SHOWERS WOULD BE ACROSS THE HIGHER ELEVATIONS IN UPSLOPE
FAVORED AREAS...AS WELL AS ACROSS WESTERN AREAS WHERE SOME
ADDITIONAL LAKE MOISTURE MAY BE PULLED INTO THE AREA. WOULD NOT
EXPECT MUCH ACCUM AT ALL DUE TO LIGHT QPF VALUES. MAX TEMPS WILL
AVERAGE NEAR NORMAL FOR SUN NIGHT INTO MONDAY...WITH MON MAX TEMPS
IN THE MIDDLE TO UPPER 30S FOR VALLEY AREAS.
ON MONDAY NIGHT...A STRONG ARCTIC FRONT WILL DROP ACROSS THE REGION.
SOME ADDITIONAL SNOW SHOWERS AND SQUALLS ARE POSSIBLE JUST AHEAD AND
ALONG THE SFC BOUNDARY. IN THE WAKE OF THIS SYSTEM...850 HPA WILL
DROP AS LOW AS -20 TO -23 DEGREES C...WHICH LOOKS TO BE THE COLDEST
850 HPA TEMPS OF THE SEASON SO FAR. THIS WILL ALLOW FOR QUITE COLD
CONDITIONS FOR TUESDAY INTO TUESDAY NIGHT...WHEN SINGLE DIGITS LOWS
WILL BE POSSIBLE IN MANY AREAS...WITH READINGS BELOW ZERO IN PARTS
OF THE DACKS FOR TUES NIGHT AS WELL. WILL HAVE TO WATCH FOR SOME
POTENTIAL FOR WIND CHILLS TO REACH NEAR ADVISORY CRITERIA IN THE
HIGHEST ELEVATIONS OF THE ADKS. MOST OF TUES THROUGH TUES NIGHT WILL
BE DRY...ALTHOUGH AREAS DOWN WIND OF LAKE ONTARIO COULD SEE SOME
LAKE EFFECT WITH THE FAVORABLE LAKE/AIR DELTA T. THIS LOOKS TO BE A
NW FLOW...SO THAT WOULD FAVOR MULTI BANDS REACHING THE WESTERN
MOHAWK/SCHOHARIE VALLEY AND CATSKILLS.
TEMPS ALOFT WILL BEGIN TO MODERATE ON WEDNESDAY AS HIGH PRESSURE
SLIDES OVER THE REGION...WHICH SHOULD HELP LOWER THE INVERSION
HEIGHT AND SQUELCH THE LAKE EFFECT AS WELL. STILL...MAX TEMPS LOOK
COLD...WITH VALLEY READINGS STILL BELOW NORMAL IN THE MIDDLE 20S.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 600 PM...THE AREA LIGHT SNOW/SNOW SHOWERS OVER THE REGION HAD
DIMINISHED WITH NOTHING MORE THAN A SNOW FLURRY POSSIBLE AT THE
KGFL/KALB/KPOU TAF SITES UNTIL ABOUT 02Z...BUT DUE DIMINISHING RADAR
RETURNS AND INCREASINLY DRIER AIR AT THE SURFACE...DID NOT MENTION
THE CHANCE OF A FLURRY IN THE TAFS.
OTHERWISE...VFR SC DECK EXPECTED AT ALL THREE TAF SITES TO START THE
TAF PERIOD...BECOMING SCT AT KPOU AFTER 06Z...AND NOT UNTIL THURSDAY
AFTERNOON AND KALB AND KGFL.
SURFACE WINDS TO SART THE TAF PERIOD WILL BE NORTHWEST AT 10 TO 12
KTS WITH GUSTS OF 15 TO 20 KTS. THE WINDS WILL DIMINISH TO 5 TO 10
KTS BY AROUND MIDNIGHT...AND LIKELY BECOME LIGHT AND VARIABLE AT
KGFL/KPOU. EXPECT NORTH WINDS AROUND 5 KTS ON THURSDAY.
OUTLOOK...
THU NITE-FRI...VFR...NO SIG WX.
FRI NGT...VFR DETERIORATING TO MVFR LATE AS A WINTRY MIX MOVES
IN.
SAT-SAT NGT...MVFR-IFR...WITH A WINTRY MIX. A CHANGE OVER TO
PLAIN RAIN DURING THE AFTERNOON AND EVENING. AT KPOU BY LATE
MORNING...AT KALB BY EARLY AFTERNOON AND POSSIBLY AT KGFL DURING
THE AFTERNOON.
SUN...VFR...MVFR POSSIBLE WITH A CHC -FZRA IN THE AM AND CHC
SHRA/-SHSN IN THE AFTERNOON.
&&
.HYDROLOGY...
NOTE...THE WATERFORD GAGE /WTFN6/ IS STILL EXPERIENCING ICE ON THE
SENSOR AND IS RESULTING IN INACCURATE READINGS. RFC/USGS AND
WATERFORD POLICE DEPARTMENT HAVE BEEN CONTACTED SINCE NO FLOODING
NOR ICE JAMS ARE OCCURRING. THE AHPS WEB PAGE HAS BEEN NOTATED AT
THIS TIME.
THE MONITORING EQUIPMENT ON THE MOHAWK AT LITTLE FALLS HAS ALSO
BECOME FROZEN AND IT IS INOPERATIVE. GAGES ON THE MOOSE RIVER AT
MCKEEVER AND ON THE SCHOHARIE CREEK AT PRATTSVILLE ARE WORKING
BUT READING ABOUT TWO FEET HIGHER DUE TO THE EFFECT OF ICE IN
THE RIVER.
COLD WEATHER WILL CONTINUE ACROSS THE REGION WITH A GRADUAL WARMING
TREND THROUGH CHRISTMAS DAY. DURING THIS TIME...TEMPERATURES ARE
FORECAST TO AVERAGE WELL BELOW FREEZING ACROSS THE ENTIRE FORECAST
AREA...WHICH WILL LIKELY RESULT IN THE FORMATION OF SOME ICE
ON MANY RIVERS. ACCUMULATING ICE MAY CAUSE SOME RIVER LEVELS TO RISE
EVEN THOUGH FLOWS CONTINUE TO DIMINISH.
STARTING MIDDAY CHRISTMAS DAY...THE PRECIP SHIELD FROM THE STORM IN
THE MIDWESTERN STATES WILL BEGIN TO AFFECT US WITH A MIX OF SNOW...
SLEET...AND RAIN. LITTLE...IF ANY...MELTING IS EXPECTED TO TAKE
PLACE UNTIL SATURDAY WHEN WARMER AIR BEGINS TO MIX DOWN TO THE
SURFACE AND BRING TEMPERATURES INTO THE UPPER 30S AND LOW 40S FROM
THE MOHAWK VALLEY SOUTH. MUCH OF THIS AREA HAS RELATIVELY LITTLE
SNOW ON THE GROUND...AND WITH A FLOW OF WARM AIR OFF THE OCEAN
THE RAIN COULD BE HEAVY AT TIMES ON SATURDAY. THIS WOULD BRING
ABOUT SIGNIFICANT INCREASES IN RIVER FLOWS...WHICH IN TURN COULD
BREAK SOME OF THE ICE LOOSE. ASIDE FROM BACKUPS OR SURGES FROM ICE
JAMS...NOT ENOUGH RUNOFF IS EXPECTED TO CAUSE FLOODING AT THIS
TIME.
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...GJM
NEAR TERM...GJM
SHORT TERM...HWJIV
LONG TERM...FRUGIS
AVIATION...GJM
HYDROLOGY...RCK
