January 29, 2012 Forecast Discussion

000
FXUS61 KALY 291513
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1013 AM EST SUN JAN 29 2012

.SYNOPSIS…
THE PARADE OF FAST MOVING WEATHER SYSTEMS WILL CONTINUE
ACROSS THE NORTHEAST. HIGH PRESSURE RIDGED ALONG THE MID ATLANTIC
COAST WILL MOVE OFFSHORE THIS AFTERNOON…AS TWO COLD FRONTS WILL
MOVE ACROSS THE REGION THIS EVENING AND OVERNIGHT. ON MONDAY…HIGH
PRESSURE WILL BRIEFLY MOVE OVER THE NORTHEAST…THEN IT WILL SHIFT
OFFSHORE MONDAY NIGHT…AND A WARM FRONT WILL SET UP FROM THE UPPER
GREAT LAKES TO CAPE COD BY TUESDAY…PRODUCING SOME LIGHT SNOW FOR
THE REGION.

&&

.NEAR TERM /THROUGH TONIGHT/…
AS OF 950 AM EST…WE CANCELED THE LAKE EFFECT SNOW ADVISORY FOR
NRN HERKIMER CTY…AS THE BAND AS SHIFTED NORTH OF THE AREA IN THE
BACKING LOW-LEVEL FLOW TO THE SW. THE BAND IS NOW IN THE ST
LAWRENCE RIVER VALLEY. SNOW TOTALS FROM THE LAKE EFFECT AND SNOW
SQUALLS THE PAST 12 TO 15 HOURS HAVE RANGED FROM 3 TO 7 INCHES
WITH SOME ISOLATED HIGHER AMOUNTS POSSIBLE. PLEASE SEE OUR LATEST
PNS STATEMENT.

THE TREND WILL BE FOR A BRIEF BREAK IN THE LATE MORNING INTO THE
EARLY PM FOR MOST OF THE REGION WITH THE RIDGING FROM THE SOUTH.
HOWEVER…ANOTHER POTENT SHORT-WAVE TROUGH IS APPROACHING FROM NRN
IL THIS MORNING. THIS STRONG UPPER LEVEL DISTURBANCE AND ITS
ASSOCIATED COLD FRONT WILL INCREASE THE CHANCE OF SNOW SHOWERS AND
ISOLD SQUALLS FROM WEST TO EAST LATE THIS AFTERNOON INTO THE
OVERNIGHT PERIOD. ONCE AGAIN…BASED ON THE 3-KM REF PRODUCT FROM
THE HRRR AND THE HIRES WRF FAVORS 00Z-03Z. THE HRRR IS FASTER WITH
A 22Z-01Z TIMING WITH THE FIRST BOUNDARY. A SECOND STRONGER
BOUNDARY WITH THE UPPER TROUGH…THE HRRR HAS APPROACHING
BTWN 03Z-06Z FOR THE FCST AREA. WE TRENDED THE SKY COVER TO PARTLY
TO MOSTLY SUNNY FROM THE HUDSON RIVER VALLEY EASTWARD INTO THE
EARLY TO MID PM…BEFORE THE CLOUD INCREASE AHEAD OF THE FIRST
FRONT. MAX TEMPS WILL STILL RUN ABOVE NORMAL WITH U30S TO L40S IN
THE VALLEYS…AND U20S TO M30S OVER THE MTNS. T/TD/RH/APPARENT
TEMP TRENDS WE REDONE BASED ON OBSERVATIONS. THE HIGHEST SNOW
ACCUMULATIONS WITH THIS DISTURBANCE LOOK LIKE THEY WILL BE NORTH
AND WEST OF OF THE CAPITAL REGION WITH 1 TO 4 INCHES POSSIBLE
/ESPECIALLY THE WRN DACKS AND WRN MOHAWK VALLEY/.

PREVIOUS NEAR TERM…

LAKE EFFECT BAND STILL PERSISTENT…AND SHOULD CONTINUE UNTIL WARM
ADVECTION BEGINS LATER THIS MORNING…WHEN THE BAND SHOULD BECOME
DISRUPTED. ALSO SOME ISOLATED SNOW SHOWERS AND FLURRIES STILL INTO
THE SCHOHARIE VALLEY. KEEPING THE SNOW IN THE FORECAST FOR THE
NEXT COUPLE OF HOURS IN THE SCHOHARIE VALLEY AND WESTERN MOHAWK
VALLEY…WHILE KEEPING THE NORTHERN HERKIMER AREA IN BETTER
CHANCES THROUGH THE MORNING. ONE REPORT OF JUST OVER A FOOT
WAS JUST RECEIVED…BUT KEEPING ADVISORY UP AS MOST AREAS SHOULD
SEE 7 INCHES OR LESS.

CLOUD COVER HIGHLY DEPENDENT ON LAKE EFFECT MOISTURE THIS MORNING
BUT THERE SHOULD BE LESS CLOUD COVER ONCE THE LAKE EFFECT BAND IS
DISRUPTED THIS AFTERNOON. SO…JUST SOME MINOR ADJUSTMENTS TO SKY
COVER AND TEMPERATURES THROUGH THIS MORNING.

PREV AFD BELOW…

LAKE EFFECT BAND STILL EXTENDING INTO THE WESTERN MOHAWK VALLEY AND
SOUTHERN ADIRONDACKS. IT IS A BIT CELLULAR AS THE DEPTH OF THE
MOISTURE AND INSTABILITY IS RELATIVELY DEEP…EVIDENT IN THE 00Z BUF
SOUNDING. THE BAND SHOULD CONTINUE TO BRING SNOW INTO THE AREA
THROUGH THE EXPIRATION OF THE WINTER WEATHER ADVISORY. SOME ISOLATED
REFLECTIVITIES ARE RESPECTABLE BUT BASED ON THERMAL PROFILES AND THE
RAPIDLY CHANGING CHARACTER OF THE BAND…SNOW RATIOS AND DURATION OF
HEAVIEST SNOW SEEMS TO SUGGEST SNOW SHOULD STAY WITHIN THE ADVISORY
RANGE. SNOWFALL AMOUNTS STILL LOOK TO BE UP TO 7 INCHES. SOME
ISOLATED SNOW SHOWER ACTIVITY ALSO EXTENDING INTO THE SCHOHARIE
VALLEY THROUGH THE EARLY MORNING HOURS BUT LIGHTER AND MORE
SCATTERED THAN THE SINGLE BAND TO THE NORTH.

WARM ADVECTION WILL BEGIN BY LATE MORNING…SO THE SINGLE BAND AND
THE SCATTERED ACTIVITY TO THE SOUTH IN THE SCHOHARIE VALLEY SHOULD
GET DISRUPTED AROUND OR SHORTLY AFTER SUNRISE. THERE SHOULD BE SOME
PERIODS OF SUN THROUGH AT LEAST THE MORNING…MAYBE INTO THE
AFTERNOON…ESPECIALLY IN EASTERN AREAS…DEPENDING ON HOW QUICKLY
THE NEXT SYSTEM APPROACHES FROM THE GREAT LAKES. BASED ON MIXING
POTENTIAL TODAY…HIGHS IN THE UPPER 30S TO MID 40S BEFORE CLOUD
COVER ARRIVES. HIGHS IN THE LOWER TO MID 30S IN THE SOUTHERN
ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS.

NEXT QUICK MOVING NORTHERN STREAM SYSTEM TRACKS THROUGH THE REGION
TONIGHT…WHICH LOOKS TO BE RELATIVELY MOISTURE STARVED…EXCEPT FOR
WHAT COULD BE PICKED UP OFF THE GREAT LAKES. STILL…MOSTLY CLOUDY
MUCH OF THE NIGHT…WITH THE MOST WIDESPREAD SNOW SHOWER ACTIVITY IN
THE WESTERN MOHAWK VALLEY AND SOUTHERN ADIRONDACKS. SCATTERED
ACTIVITY SHOULD MAKE IT INTO MOST OF THE REGION…WITH MORE ISOLATED
ACTIVITY IN THE MID HUDSON VALLEY..SOUTHERN BERKSHIRES AND NW CT.
THERE COULD BE 1 TO 3 INCHES OF SNOW IN THE NORTHERN AREAS WITH
LOCAL DUSTINGS POSSIBLE ACROSS THE REST OF THE REGION. SOME PARTIAL
CLEARING IS POSSIBLE TOWARD SUNRISE…BUT GUSTY WEST TO NORTHWEST
WINDS SHOULD BEGIN AS THE SYSTEM EXITS LATE TONIGHT. LOWS IN THE
20S…BUT A LITTLE HIGHER THAN GUIDANCE NUMBERS DUE TO THE WINDS AND
MIXING. SOME LOWS IN THE TEENS IN THE SOUTHERN ADIRONDACKS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/…
BACK DOOR CDFNT PUSHES SOUTH INTO FCA AS 500HPA SHORT WVS MOVE
EAST ACROSS NEW YORK NEW ENG. THIS WILL BRING A BRIEF PERIOD OF
COLD AIR AND REINVIGORATE LK EFFECT BAND INTO TUG HILL/W ADNDKS.
BY MON NT. LATE MONDAY INTO TUES EASTERN TROF DEPARTS…RIDGING
BUILDS FROM GRTLKS TO SE STATES AND A 500HPA SHORT WAVE EJECTS INTO
NORTHERN GREAT PLAINS. THIS SETS UP FRONTOGENESIS AS WMFNT ORGANIZES
DLH-BOS. MONDAY AND MONDAY NIGHTS CLOUDS BLOOM ALL ALONG AND AHEAD OF
IT…AND OVERRUNNING SNOW BREAKS OUT ACROSS THE GRTLKS.

MON NT INTO TUE MORNING THIS -SN SPREADS ACROSS NY/NEW ENG. THE
NAM/GFS/ECMWF ARE SIMILAR BUT NAM QPF IS DEFINITELY LIGHTER. THE
GEM HAS BULK OF PCPN N OF FCA. AS THE 500HPA FLOW TURNS SW THE
MODEL SUIT GENERALLY LIFTS TO WMFNT OUT OF THE FCA TUE
EVNG…LEAVING AREA IN WARM SECTOR WITH -SHRA THREAT TILL CDFNT
MOVES THROUGH WED. THEY ALL TAKE MAJOR CYCLONE WITH THIS SYSTEM
WELL NORTH INTO ONT/QB.

TEMPS ARE GENERALLY ABV NORMAL TO MUCH ABV DURING THIS PERIOD.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/…
THE FAST MOVING PATTERN CONTINUES WITH A SHORT WV MOVING THROUGH
THUR TRIGGERING ISOLD TO SCT -SHSN…MORE NEAR THE LAKE. HIGH
PRESSURE RIDGES SOUTH TO END THE WEEK WITH DRY CONDS…THEN THE
MODELS TAKE THE BIG DIVERGE. THE GFS PRODUCES A SIGNIFICANT
COASTAL LOW…AS USUAL BASED ON THE PHASING OF SHORT WAVES THAT
ARE SCATTERED ALL OVER EAST ASIA. THE ECMWF TAKES THIS STORM…NOT
UP THE EAST COAST…BUT UP THE ST LAWRENCE VLY. THE MODEL SUITE
HAS BEEN ALL OVER WITH THIS SYSTEM FROM IN THE WEST ATLC. FOR NOW
CARRIED CHC OR SLIGHT CHC. THERE`S 6 DAYS TO THE MODELS TO DEBATE
WITH THEMSELVES HOW THE SHORT WVS WILL PHASE. TEMPS DURING THE EFO
WILL BEGIN ABV NORMALS THU AND END THE PERIOD NEAR NORMAL.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/…
JUST SOME SCATTERED CLOUDS ABOVE 3000 FEET THROUGH THE MORNING…
THEN MID AND HIGH CLOUDS MOVE IN AHEAD OF THE NEXT SYSTEM THIS
AFTERNOON. SOME SCATTERED SNOW SHOWER ACTIVITY IS POSSIBLE AT KGFL
AND KALB AFTER 00Z SO ACKNOWLEDGING VCSH THERE. MOST OF THE SNOW
SHOWER ACTIVITY SHOULD STAY NORTH OF THE KPOU AREA. THE SNOW
SHOWERS SHOULD EXIT AFTER MIDNIGHT.

LIGHT WEST TO SOUTHWEST WINDS WILL INCREASE TO 10 TO 15 MPH AROUND
MID MORNING. GUSTY SOUTHWEST TO WEST WINDS SHOULD CONTINUE
THROUGH EARLY AFTERNOON AT 10 TO 15 MPH…WITH GUSTS OVER 20 MPH.
WINDS WILL BECOME SOUTH TO SOUTHWEST THIS AFTERNOON AT 10 MPH OR
LESS. ONCE THE SNOW SHOWER ACTIVITY MOVES OUT TONIGHT…WINDS
SHOULD SHIFT TO WEST AND NORTHWEST AT 10 TO 15 MPH…AND COULD GET
GUSTY.

OUTLOOK…
SUN NIGHT…VFR/MVFR. CHC -SHSN.
MON-TUE…VFR. NO SIG WX.
TUE NIGHT-WED…VFR/MVFR. CHC -SHRA/-SHSN.
THU…VFR…SLIGHT CHC -SHRA/-SHSN.

&&

.HYDROLOGY…
RIVER FLOWS CONTINUE TO RECEDE. A CLIPPER LOW PRESSURE SYSTEM AND
TWO COLD FRONTS WILL IMPACT THE REGION THIS EVENING INTO MONDAY
MORNING. SOME SCATTERED SNOW SHOWERS AND FLURRIES WILL BE COMMON
WITH LIGHT SNOW ACCUMULATIONS UP TO A FEW INCHES IN THE SOUTHERN
ADIRONDACKS. A WARM FRONT WILL ALSO BRING SOME LIGHT SNOW MONDAY
NIGHT INTO TUESDAY MORNING.

OVERALL…RIVER FLOWS WILL CONTINUE TO RECEDE INTO THE MID WEEK
ADN ANY RAINFALL THAT OCCURS WILL BE LIGHT AND MOST PRECIPITATION
DURING THE WEEK WILL BE LIGHT SNOW.

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…SNYDER/WASULA
NEAR TERM…NAS/WASULA
SHORT TERM…SNYDER
LONG TERM…SNYDER
AVIATION…NAS
HYDROLOGY…NAS/WASULA

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