January 12, 2012 Forecast Discussion

000
FXUS61 KALY 121803
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
102 PM EST THU JAN 12 2012

.SYNOPSIS…
SCATTERED LIGHT RAIN AND SNOW SHOWERS WILL CONTINUE TODAY. ANOTHER
LOW PRESSURE SYSTEM WILL MOVE NORTHEAST FROM THE OHIO VALLEY TONIGHT
INTO FRIDAY WITH RAIN AND SNOW SHOWERS SOUTH AND WINTRY
PRECIPITATION NORTH…TRANSITIONING TO SNOW EVERYWHERE BY LATE
FRIDAY. BY FRIDAY AFTERNOON IT WILL FEEL LIKE WINTER WITH
BLUSTERY…COLD CONDITIONS.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 1245 PM…MOST OF THE MODERATE TO HEAVY PRECIPITATION ECHOES
HAVE EXITED THE AREA. STILL SOME ECHOES OCCURRING OVER THE SOUTHERN
ADIRONDACKS. WITH TEMPS THERE GENERALLY BELOW FREEZING…PROBABLY
WINTRY PRECIPITATION. TEMPERATURES ARE ALSO STILL BELOW FREEZING IN
MANY AREAS OF THE GREEN MOUNTAINS IN SOUTHERN VERMONT AND POCKETS OF
BELOW FREEZING TEMPS CONTINUE IN THE BERKSHIRES AND CATSKILLS. TEMPS
IN THE HUDSON AND HOUSATONIC VALLEYS HAVE GENERALLY WARMED TO THE
MID 30S TO NEAR 40. ADJUSTED TEMPS/POPS/WEATHER TO ACCOUNT FOR
CURRENT OBS AND TO BLEND WITH FORECAST THROUGH TOMORROW MORNING. FOR
SNOWFALL TOTALS PLEASE SEE /PNSALY/.

PREVIOUS NEAR TERM DISCUSSION**
AS OF 1100 AM…DROPPED WEATHER ADVISORIES FOR OUR HUDSON VALLEY
FROM THE CAPITAL DISTRICT SOUTHWARD….AS WELL AS WESTERN ULSTER
COUNTY AND NORTHERN LITCHFIELD COUNTY. SOME OF THESE AREAS HAVE BEEN
REPORTING A MIX…BUT WITH TEMPERATURES ABOVE FREEZING…NO MORE
ACCUMULATIONS ARE EXPECTED.

WE KEPT THE WINTER WEATHER ADVISORY UP FOR MOST OF THE THE HIGHER
TERRAIN SURROUNDING THE CAPITAL DISTRICT AS TEMPERATURES WERE STILL
IN SOME CASES…BELOW FREEZING. THE ADVISORY IS MAINLY FOR POCKETS
OF FREEZING. WITH THE EXCEPTION OF THE ADIRONDACKS…ANY ADDITIONAL
ACCUMULATIONS IN THESE AREA OF SNOW WOULD ONLY 1-2 INCHES. THE
ADIRONDACKS COULD SEE UP TO 3 INCHES ADDITIONAL SNOWFALL…BUT MOST
AREAS EVEN THERE WILL CLOSE TO AN INCH.

TEMPERATURES WILL SLOWLY RISE TO AT OR ABOVE FREEZING HIGHER TERRAIN
AND AREA NORTH OF ALBANY…WITH VALLEY AREAS 35 TO 40. SOME AREAS
PRIMED TO DOWNSLOPING WINDS OFF THE HIGHER TERRAIN COULD REACH INTO
THE LOWER 40S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/…
PSEUDO WARM FRONT LIFTS NORTHWARD THURSDAY EVENING AS MID LEVEL DRY
SLOT ADVANCES NORTHWARD ACROSS THE REGION. BUFR PROFILES DO SUGGEST
AMPLE LOW LEVEL MOISTURE WHICH WILL BE CLOSE TO THE -10C ALOFT FOR
ENOUGH ICE NUCLEI TO WARRANT THE LOW CHANCE POPS FOR THE REGION
OVERNIGHT. MAIN DYNAMICS WITH OHIO VALLEY SYSTEM BEGINS TO ENCROACH
OUR WESTERN ZONES WELL AFTER MIDNIGHT WHERE WE WILL INCREASE POPS.
THERMAL PROFILES WILL REMAIN A CHALLENGE…ESPECIALLY FOR PORTIONS
OF THE MOHAWK VALLEY AND DACKS WHERE SURFACE TEMPERATURES ARE
EXPECTED TO DROP BACK INTO THE UPPER 20S AND LOWER 30S. THIS POSES
A PROBLEM WITH THE CHANCE FOR FREEZING RAIN/DRIZZLE DUE TO THE
AFOREMENTIONED POTENTIAL LACK OF ICE NUCLEI.

POTENT MID LEVEL JET COINCIDING WITH IMPRESSIVE FRONTOGENESIS WILL
MAKE FOR AN INTERESTING WEATHER ON FRIDAY MORNING. QG DIAGNOSTIC
FIELDS ARE IMPRESSIVE WITH RAPIDLY INCREASING VERTICAL VELOCITIES
OVER THE CWA AND STEEPENING MID LEVEL LAPSE RATES. WOULD NOT BE
SURPRISED TO FIND A FEW SQUALLS EMBEDDED ALONG THE ARCTIC COLD FRONT
THAT WILL MOVE EAST OF THE CWA BY LATE MORNING FRIDAY /AS SUGGESTED
IN THE EXPERIENTIAL HIRES WINDOWS OF MESOSCALE MODELS/. IN
FACT…TEMPERATURES IN THE WAKE OF THE FROPA SHOULD DROP BACK BELOW
FREEZING WHICH COULD RESULT IN BLACK ICE FORMATION WHERE SURFACES
ARE NOT TREATED. LINGERING SURFACE TROUGH AXIS AND DEFORMATION
DYNAMICS OVER WESTERN AND EASTERN NY COULD PROLONG THE SNOWFALL
WHICH WILL BE MONITORED CLOSELY. FURTHERMORE…LAKE ONTARIO
CONTRIBUTION IS EXPECTED TO INCREASE FRIDAY AFTERNOON INTO FRIDAY
NIGHT WITH A 270-280 WIND DIRECTION AND INCREASING LAKE DELTA T/S.
SEVERAL INCHES OF SNOW /AND BLOWING SNOW/ ARE POSSIBLE FOR PORTIONS
OF THE MOHAWK VALLEY…SOUTHERN DACKS. DUE TO FORECAST CHALLENGES
THAT REMAIN WITH RESPECT TO THE WIND TRAJECTORIES AND THE TIMING OF
THE INVERSION LEVELS DROPPING BELOW 5K FEET…WE WILL NOT HOIST ANY
HEADLINES AT THE PRESENT TIME. WE WILL HIGHLIGHT IN THE HWO.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/…
OVER THE WEEKEND…THE NORTHEAST WILL BE DOMINATED BY A LARGE SCALE
TROUGH. THIS WILL KEEP TEMPS A LITTLE COOLER THAN THEY HAVE BEEN
RECENTLY AND SOMEWHAT BELOW NORMAL. HOWEVER…IT WON/T BE BRUTALLY
COLD BY ANY STRETCH. THE 12 UTC GEFS IS SHOWING 850 HPA TEMPS
GENERALLY NEAR NORMAL…WITH A BRIEF PERIOD OF ABOUT 1-2 STD BELOW
NORMAL. THE LATEST DETERMINISTIC 12 UTC GFS IS SHOWING 850 HPA
TEMPS OF AROUND -15 DEGREES C FOR SATURDAY…AND -16 TO -18 DEGREES
ON SUNDAY. THIS WILL TRANSLATE TO MAX TEMPS IN THE 20S TO LOW 30S ON
SATURDAY…AND MAX TEMPS IN THE TEENS TO LOW 20S FOR SUNDAY. MIN
TEMPS ON SAT AND SUN NIGHTS WILL GENERALLY BE IN THE SINGLE
DIGITS…WITH BELOW ZERO READINGS ACROSS THE HIGH TERRAIN. WHILE
THIS WILL PROBABLY WIND UP BEING SOME OF THE COLDER NIGHTS OF THE
SEASON SO FAR…IT/S STILL NOT FAR FROM WHAT IS CONSIDERED NORMAL OR
EXPECTED FOR THIS TIME OF THE YEAR.

IT WILL REMAIN FAIRLY DRY OVER THE WEEKEND. THE CYCLONIC FLOW MAY
ALLOW FOR SOME CLOUDS…ESP IN AREAS DOWNWIND OF LAKE ONTARIO.
HOWEVER…THE FLOW WON/T BE OVERLY CONDUCIVE FOR LAKE EFFECT…AND
INVERSION HEIGHTS OF ONLY AROUND 1 KM WILL KEEP ANY LAKE EFFECT SNOW
SHOWERS AS FAIRLY LIGHT AND CONFINED CLOSE TO THE LAKE SHORE. WILL
ONLY ALLOW A BRIEF PERIOD CHC POPS FOR PARTS OF THE MOHAWK
VALLEY/SCHOHARIE COUNTY FOR SAT MORNING…BEFORE LOWERING POPS TO
SLIGHT CHC FOR THE REMAINDER OF SATURDAY.

HIGH PRESSURE WILL MOVE ACROSS THE REGION FOR MONDAY. THIS WILL
CONTINUE THE DRY WEATHER. TEMPS WILL CONTINUE TO BE A LITTLE ON THE
COOL SIDE…BUT NOTHING UNHEARD OF FOR MID JANUARY…WITH 20S FOR
MOST AREAS. SOME CLOUDS WILL BEGIN TO INCREASE FOR MONDAY NIGHT
AHEAD OF AN APPROACHING STORM SYSTEM. MIN TEMPS MAY ACTUALLY WIND
UP BEING EARLIER IN THE NIGHT…AS TEMPS MAY SLOWLY RISE OVERNIGHT
WITH AN INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW. FOR NOW…HAVE
GONE WITH MIN TEMPS IN THE TEENS IN MOST AREAS.

A STRENGTHENING LOW PRESSURE AREA WILL RACE FROM THE UPPER GREAT
LAKES TOWARDS NORTHERN QUEBEC ON TUESDAY. AN ARCTIC FRONT ASSOCIATED
WITH THIS STORM SYSTEM WILL SWING THROUGH OUR AREA ON TUESDAY. THIS
WILL ALLOW FOR SOME RAIN/SNOW SHOWERS…WITH P-TYPE DEPENDENT ON
ELEVATION/BOUNDARY LAYER TEMPS. MOST VALLEY AREAS WILL PROBABLY WARM
UP JUST ENOUGH TO KEEP MOST OF THE PRECIP AS RAIN…ESP CONSIDERING
THIS STORM IS COMING FROM THE WEST WITH A STORM SYSTEM TRACKING WELL
NORTH OF THE AREA. TEMPS LOOK TO REACH THE 30S IN VALLEY
AREAS…WITH MAX TEMPS IN THE UPPER 20S TO NEAR FREEZING IN THE HIGH
TERRAIN. PRECIP WILL BE SHOWERY IN NATURE AND QPF WILL BE RATHER
LIGHT…WITH LESS THAN A QUARTER OF AN INCH IN MOST AREAS.

IN THE WAKE OF THIS SYSTEM…COOLER AIR WILL AGAIN FILTER INTO THE
REGION FOR TUESDAY NIGHT INTO WEDNESDAY. SOME LAKE EFFECT COULD
AFFECT FAR WESTERN AREAS. TEMPS LOOK TO GO BACK BELOW NORMAL FOR
WEDNESDAY…WITH MAINLY TEENS AND 20S FOR MAX TEMPS.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/…
LOW CONFIDENCE FORECAST FOR MAINLY THE TONIGHT PERIOD.

THE STORM THAT IMPACTED THE TAFS EARLIER…WAS PULLING AWAY TO THE
EAST OF LONG ISLAND. IN ITS WAKE…LOTS OF MVFR CLOUDS WILL PERSIST.
THEN…ANOTHER DISTURBANCE AND COLD FRONT WILL APPROACH THE TAF
SITES ON FRIDAY…BRINGING MUCH COLDER AIR BEHIND IT.

THE BULK OF THE PRECIPITATION ASSOCIATED WITH THE STORM…IS
FINISHED. THERE MIGHT BE SOME OCCASIONAL DRIZZLE BUT THAT SHOULD BE
MAINLY IT THROUGH THIS EVENING. WILL CONTINUE WITH THE VCSH TO
REFLECT THE POSSIBILITY OF SHOWERS THROUGH THE EVENING.

SHOWERS WILL BREAK OUT LATER OVERNIGHT INTO FRIDAY…MIXING WITH
SNOW BY MIDDAY AT ALL TAF SITES.

THE PROBLEM TONIGHT IS RIGHT NOW WE ARE ASSUMING THE CLOUDS WILL
HOLD. IF THEY DO…ALL THE TAFS WILL LIKELY HAVE MVFR CONDITIONS
(MAINLY CIG…AOB 2000 FEET). HOWEVER…IF THE CLOUDS WERE TO THIN
OR EVEN CLEAR OUT (WHICH WE LEAN AGAINST BUT CERTAINLY
POSSIBLE)…SOME IFR FOG IS POSSIBLE…ESPECIALLY AT KGFL. THE WIND
ALOFT LOOKS REMAIN 30KTS OR HIGHER (WELL OFF THE DECK) WHICH SHOULD
HELP MITIGATE THE FORMATION OF IFR FOG. FOR NOW…NO MENTION OF IFR
UNTIL THE SHOWERS BEGIN TURNING TO SNOW…WHICH LOOKS TO BE AROUND
15Z FRIDAY. HOWEVER…IF THE FRONT MOVES IN FASTER…THE CHANGEOVER
COULD EVEN BE A LITTLE QUICKER.

THE NORTHERLY WIND 5-10 KTS WILL TURN SOUTHERLY LATER TOWARD
EVENING. THEY WILL TEND TO INCREASE A LITTLE OVERNIGHT…ESPECIALLY
AT KALB. THEN…THEY WILL SHIFT INTO THE WEST OR SOUTHWEST…AND
BECOME GUSTY AT KALB.

NOT SHOWN IN THE TAFS IS THAT THE WIND LOOKS TO BECOME STRONG AT ALL
THE TAF SITES BY LATER FRIDAY AFTERNOON…POSSIBLY GUSTING TO OVER
30KTS…ESPECIALLY AT KALB. THERE MIGHT ALSO BE INTENSE SNOW SQUALLS
BRIEFLY REDUCING VISIBILITY TO WELL UNDER A MILE.

BEST TO CHECK IN WITH THE FORECAST/DISCUSSION FOR LATER UPDATES.

OUTLOOK…
FRI NT…MAINLY VFR…WINDY. CHC MVFR -SHSN.
SUN-MON…VFR…NO SIG WX.
TUE…VFR…CHC MVFR -RASN.
&&

.HYDROLOGY…
A COMPLEX STORM SYSTEM CURRENTLY IMPACTING THE FA WILL CONTINUE TO
BRING MIX PRECIPITATION TO THE HYDROLOGIC SERVICE AREA THIS MORNING
TRANSITIONING TO ALL RAIN…ESPECIALLY SOUTH AND EAST OF THE SOUTHERN
ADIRONDACKS BY THE AFTERNOON. THE PRECIPITATION WILL BE ASSOCIATED
WITH A COASTAL OR SECONDARY LOW THAT WILL MOVE NORTHEAST OF LONG
ISLAND BY THIS AFTERNOON. THE PRIMARY LOW WILL REMAIN TO THE WEST
OVER THE OHIO VALLEY AND THE GREAT LAKES REGION. TOTAL LIQUID
EQUIVALENT VALUES WILL RANGE FROM A HALF AN INCH TO AROUND AN INCH
BY THURSDAY EVENING. WE ARE EXPECTING SOME DOWNSLOPING TO REDUCE
TOTAL QPF AMOUNTS TO AROUND A HALF AN INCH TO TWO THIRDS OF AN INCH
IN THE UPPER HUDSON VALLEY…AND PORTIONS OF THE LAKE GEORGE REGION.
THE HEAVIEST QPF WILL TEND TO BE SOUTH AND WEST OF THE CAPITAL
REGION. WE ARE EXPECTING MINIMAL IMPACT ON THE MAIN STEM RIVERS WITH
SOME MINOR RISES AT BEST. MOST OF THE PRECIPITATION WILL FALL AS
SNOW…SLEET AND FREEZING RAIN OVER THE NORTHERN BASINS.

TONIGHT…A BRIEF LULL WILL OCCUR BETWEEN THE SYSTEMS…WITH A
DRY SLOT. THERE MIGHT BE SOME SPOTTY FREEZING RAIN OR DRIZZLE
NORTH AND WEST OF THE CAPITAL REGION WITH SPOTTY PLAIN RAIN SOUTH
AND EAST. THE NEXT STRONG UPPER LEVEL DISTURBANCE WILL BRING RAIN
AND SNOW SHOWERS ON FRIDAY….AS IT MOVES OVER UPSTATE NY. THERE
COULD EVEN BE A FEW INTENSE SNOW SQUALLS. TOTAL QPF FROM THIS
SYSTEM LOOKS LIKE TWO TENTHS OF AN INCH SOUTHEAST TO TWO THIRDS OF
AN INCH NORTHWEST. COLDER AIR AND LAKE EFFECT SNOW SHOWERS WILL
BE POSSIBLE FRIDAY NIGHT INTO THE WEEKEND.

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…WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR NYZ032-
033-042-043-082.
MA…NONE.
VT…WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
VTZ013>015.

&&

$$
SYNOPSIS…HWJIV/11/NAS
NEAR TERM…HWJIV/11
SHORT TERM…BGM
LONG TERM…FRUGIS
AVIATION…HWJIV
HYDROLOGY…11

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