March 26, 2012 Forecast Discussion

000
FXUS61 KALY 270012
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
812 PM EDT MON MAR 26 2012

.SYNOPSIS…
A COLD AIR MASS WILL BE OVER THE REGION TONIGHT…AS THE
WINDS WILL GRADUALLY SUBSIDE WITH HIGH PRESSURE BUILDING IN FROM
ONTARIO. THIS CANADIAN HIGH WILL BRING SUNNY AND BELOW NORMAL
TEMPERATURES TOMORROW…AS IT MOVES OVER NEW YORK AND NEW ENGLAND.
LOW PRESSURE APPROACHING FROM THE NORTHERN GREAT LAKES REGION…AND
SOUTHERN ONTARIO TUESDAY NIGHT…WILL BRING SOME RAIN AND SNOW
SHOWERS TO THE REGION FOR THE MID WEEK.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/…
FORECAST ON TRACK ONLY MINOR ADJUSTMENTS MADE BASED ON OBSERVATIONS.

A STARK CONTRAST TO LAST WEEK AT THIS TIME…AS AN UNSEASONABLY
COLD AIR MASS CONTINUES TO BUILD INTO THE REGION. THE WATER VAPOR
LOOP WITH H500 HEIGHTS OVERLAYED SHOWS A CLOSED H500 LOW IS MOVING
EASTWARD OVER THE GULF OF ST LAWRENCE. THE MID AND UPPER LEVEL
TROUGH AXIS HAS MOVED ACROSS THE FORECAST AREA. STRONG LOW LEVEL
COLD…AND DRY ADVECTION CONTINUES ACROSS ERN NY AND WRN NEW
ENGLAND. H850 TEMPS ARE EXPECTED TO FALL TO -10C TO -15C OVER THE
REGION TONIGHT. THE LOW LEVEL SFC PRESSURE GRADIENT WILL WEAKEN
SOME OVERNIGHT BETWEEN HIGH PRESSURE SOUTH OF JAMES BAY…AND LOW
PRESSURE IN THE CANADIAN MARITIMES…AS THE SUSTAINED WINDS OF 15
TO 30 MPH WITH GUSTS AROUND 40 MPH…WILL DIMINISH TO 10 TO 15 MPH
WITH A FEW GUSTS AROUND 20-25 MPH AFTER MIDNIGHT.

CLEAR CONDITIONS WILL PERSIST WITH THE EXTREMELY DRY LOW TO MID
LEVELS…AND THE STRONG SUBSIDENCE WITH THE APPROACHING
ANTICYCLONE. IT WILL BE COLD TONIGHT…BUT WE WENT A DEGREE OR TWO
ABOVE THE WARMER GFSMOS GUIDANCE WITH THE WINDS HOLDING UP
TONIGHT. LOWS WILL GENERALLY BE IN THE TEENS TO NEAR 20F IN THE
VALLEY LOCATIONS…AND THE SINGLE DIGITS /SRN DACKS AND SRN
GREENS/ TO MID TEENS OVER THE HILLS/MTNS.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/…
TOMORROW…COLD AND SUNNY CONDITIONS WILL PREVAIL. THE LOW-LEVEL
RH VALUES WILL FALL INTO THE TEENS OVER MOST OF THE FCST AREA BY
THE LATE MORNING INTO THE AFTERNOON. THE MIXING HEIGHTS ARE
LIKELY TO BE LOWER THIS DAY COMPARED TO MONDAY WITH THE SFC HIGH
BUILDING IN NY AND NEW ENGLAND BY THE EARLY TO MID PM. WE WENT
CLOSER TO 3 KFT AGL BASED ON THE NAM/GFS BUFKIT PROFILES FOR AN
AVG MIXING HEIGHT. HIGHS WILL GENERALLY BE IN THE U30S TO L40S IN
THE VALLEYS /A FEW M40S ARE POSSIBLE IN SRN LITCHFIELD CTY…AND
THE MID HUDSON VALLEY/…AND U20S TO M30S OVER THE MTNS. THESE MAX
TEMPS WILL ACTUALLY BE BELOW NORMAL COMPARED TO LATE MARCH NORMALS
FOR THE REGION.

TUESDAY NIGHT…THE SFC HIGH SHIFTS SOUTH AND EAST OF THE REGION
OVER THE THE MID ATLANTIC COAST. A QUICK MOVING LOW PRESSURE
SYSTEM WILL BE APPROACHING FROM THE WESTERN GREAT LAKES REGION AND
WRN ONTARIO EARLY IN THE EVENING. THE LOW AND MID LEVELS START TO
WARM…AND WE ENTER BACK INTO A WARM ADVECTION REGIME. BY
DAYBREAK WED…THE CYCLONE IS JUST NORTH OF LAKE SUPERIOR OVER SRN
ONTARIO. THE MID LEVEL RIDGE AXIS IS JUST SHIFTING EASTWARD OVER
NY AND NEW ENGLAND. THE BEST QG FORCING WITH THE THERMAL
ADVECTION/ISENTROPIC LIFT AFTER MIDNIGHT IS OVER THE NORTH
COUNTRY…SE CANADA…AND NRN NEW ENGLAND ACCORDING TO THE
GFS/NAM/CAN GEM. THE ECMWF IS A LITTLE FURTHER SOUTH WITH LIGHT
QPF…SO WE PLACED SOME SLIGHT AND LOW CHANCE POPS FOR SOME SNOW
SHOWERS/LIGHT SNOW NORTH AND WEST OF THE CAPITAL REGION PRIOR TO
DAYBREAK. ANY ACCUMULATION WILL BE LIGHT WITH A COATING TO A HALF
AN INCH. LOWS WILL GENERALLY BE IN THE MID AND UPPER 20S IN THE
VALLEYS…AND TEENS TO M20S OVER THE HILLS/MTNS.

WEDNESDAY…THE CYCLONE REMAINS NORTH OF THE ST LAWRENCE RIVER
VALLEY…WITH A SHORT-WAVE IN THE ZONAL MID-LEVEL FLOW BRINGING A
CHANCE OF RAIN SHOWERS TO THE FCST AREA. THE LARGE-SCALE FORCING
IS WEAK…AND IT MAY BEGIN AS A MIX OF RAIN AND SNOW SHOWERS IN
THE MORNING..BEFORE THE BOUNDARY LAYER WARMS WELL ABOVE FREEZING.
THE AMOUNT OF CLOUDS THAT WILL BE AROUND MAY LIMIT HIGHS TEMPS A
BIT…DESPITE H850 TEMPS RISING BACK TO +3 TO +6C. WE LEANED
CLOSER TO THE COOLER NAM MOS TEMPS. HIGHS WILL GENERALLY BE IN THE
LOWER TO M50S SOUTH AND EAST OF THE CAPITAL REGION…AND SRN BERKS
/A FEW U50S OVER THE MID HUDSON VALLEY/…AND M40S TO NEAR 50F
NORTH AND EAST.

WEDNESDAY NIGHT…THE UPPER LEVEL TROUGH ASSOCIATED WITH THE
QUASI-CLIPPER LIKE LOW MOVES OVER THE FCST AREA. THE SHORT/MEDIUM RANGE
GUIDANCE IS VARIABLE ON WHAT WILL EVOLVE…AND OCCUR. THERE IS SOME
AGREEMENT FROM THE NAM/GFS THAT A CLOSED H500 CIRCULATION WITH
THE UPPER TROUGH WILL MOVE OVER NRN NY. THE CYCLONIC VORTICITY
ADVECTION WILL GENERATE SOME SCATTERED RAIN SHOWERS…
TRANSITIONING TO SOME SNOW SHOWERS OVER THE HIGHER TERRAIN…IF
THE LOW-LEVELS COOL DOWN ENOUGH. AS THE POTENTIALLY
CLOSED…COMPACT CIRCULATION SHIFTS EAST…SOME DEFORMATION SNOW
SHOWERS MAY LINGER NORTH OF THE CAPITAL REGION…ESPECIALLY OVER
THE SRN DACKS…AND SRN VT…WITH SOME LIGHT SNOW ACCUMULATIONS
POSSIBLE /A COATING TO AN INCH OR SO/. LOWS WILL RANGE FROM THE
M30S TO L40S IN THE VALLEYS…AND U20S TO M30S OVER THE HIGHER
ELEVATIONS.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/…
LINGERING PCPN IN THE FORM OF SCATTERED RAIN AND SNOW SHOWERS IS
EXPECTED THROUGH THURSDAY MORNING WITH THE PCPN TAPERING OFF AS
SCATTERED TO WIDELY SCATTERED RAIN SHOWERS AS THE SURFACE SYSTEM
RESPONSIBLE FOR THE PCPN EXITS OFF THE NEW ENGLAND COAST THURSDAY
MORNING WITH THE UPPER LEVEL TROUGH SLIDING THROUGH THE REGION LATE
THURSDAY. EXPECT HIGHS ON THURSDAY IN THE MID 40S TO LOWER 50S.

THURSDAY NIGHT THROUGH SATURDAY IS EXPECTED TO BE DRY AS A RIDGE OF
HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION THROUGH FRIDAY NIGHT
AND THEN SLIDES OFF THE EASTERN SEABOARD ON SATURDAY. EXPECT LOWS
THURSDAY NIGHT AND FRIDAY NIGHT IN THE 20S TO MID 30S WITH THE HIGHS
ON FRIDAY AND SATURDAY IN THE MID 40S TO MID 50S.

SATURDAY NIGHT AND SUNDAY MAY BE UNSETTLED AS SURFACE SYSTEM MOVES
FROM THE SOUTHERN OHIO VALLEY THROUGH THE MID ATLANTIC REGION WHILE
A CLIPPER TYPE SYSTEM MOVES ACROSS SOUTHERN CANADA. A GREAT DEAL OF
UNCERTAINTY EXISTS DURING THIS PERIOD IF THE FA WILL BE IMPACTED
MUCH BY EITHER SYSTEM. FOR NOW WILL GO CHANCE POPS SATURDAY NIGHT
AND SLIGHT CHANCE POPS ON SUNDAY. EXPECT LOWS SATURDAY NIGHT IN THE
MID 20S TO MID 30S WITH HIGHS ON SUNDAY IN THE 50S.

OVERALL EXPECT TEMPS TO BE NEAR NORMAL WITH PCPN BELOW NORMAL DURING
THE LONG TERM PERIOD.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/…
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD…00Z/WEDNESDAY.

NORTHWESTERLY WINDS WILL CONTINUE TO BE BRISK AND GUSTY THIS
EVENING. THE GUSTINESS IS EXPECTED TO DIMINISH AFTER MIDNIGHT
WITH SUSTAINED WINDS OF 8 TO 12 KNOTS OVERNIGHT. AFTER SUNRISE THE
WINDS WILL PICK UP AND BECOME GUSTY HOWEVER NOT NEARLY AS STRONG
AS TODAY. THE PRESSURE GRADIENT ACROSS THE REGION WILL WEAKEN AS
HIGH PRESSURE BUILDS IN DURING THE DAY. WINDS WILL DIMINISH EARLY
TUESDAY EVENING AS THE HIGH TAKES CONTROL.

OUTLOOK…
TUE NIGHT…VFR…NO SIG WX.
WED-THU…VFR/MVFR. CHC RAIN. ALSO CHC SNOW KGFL.
THU NIGHT-SAT…VFR…NO SIG WX.

&&

.FIRE WEATHER…
A FIRE WEATHER WATCH HAS BEEN ISSUED FOR EASTERN NEW YORK AND
WESTERN NEW ENGLAND LATE TOMORROW MORNING THROUGH THE AFTERNOON…

A COLD AIR MASS WILL BE OVER THE REGION TONIGHT…AS THE WINDS
WILL GRADUALLY SUBSIDE WITH HIGH PRESSURE BUILDING IN FROM
ONTARIO. THIS CANADIAN HIGH WILL BRING SUNNY AND BELOW NORMAL
TEMPERATURES TOMORROW…AS IT MOVES OVER NEW YORK AND NEW ENGLAND.

THE WINDS TONIGHT WILL BE FROM THE NORTHWEST OR NORTH AT 10 TO 20
MPH WITH A FEW GUSTS 25 TO 30 MPH. THE RH VALUES WILL ONLY
INCREASE TO 55 TO 75 PERCENT TONIGHT.

TOMORROW…THE RH VALUES WILL BE EXTREMELY LOW IN THE 10 TO 20
PERCENT RANGE. THESE LOW RH VALUES WILL BE COMBINED WITH MOST
LOCATIONS RECEIVING LESS THAN A QUARTER OF AN INCH RAINFALL OVER
THE PAST WEEK OR SO IN THE PRE-GREEN UP CONDITIONS. THE WINDS
TOMORROW WILL WEAKEN SOME WITH THE HIGH BUILDING IN DURING THE DAY
BUT NORTHWEST WINDS OF 5 TO 15 MPH WITH A FEW GUSTS AROUND 25
MPH ARE POSSIBLE. AFTER EXTENSIVE COORDINATION WITH OUR USERS AND
NEIGHBORING FORECAST OFFICES…A FIRE WEATHER WATCH HAS BEEN
ISSUED FROM THE VERY LATE MORNING THROUGH THE AFTERNOON. IT IS
STILL UNCERTAIN…AND CONFIDENCE IS LOW THAT A RED FLAG WARNING
WILL BE NEEDED…SINCE THE GUSTS OR SUSTAINED WINDS MAY FALL SHORT
OF THE RED FLAG CRITERIA IN THE COLD CONDITIONS.

TOMORROW NIGHT…THE WINDS WILL BECOME LIGHT TO CALM…AND THE RH
VALUES ARE EXPECTED TO INCREASE TO 70 TO 100 PERCENT. SOME SNOW
SHOWERS WILL ALSO BE APPROACHING LOCATIONS NORTH AND WEST OF THE
CAPITAL REGION.

SOME SCATTERED RAIN AND SNOW SHOWERS ARE EXPECTED TO BRING LIGHT
LIQUID EQUIVALENTS WEDNESDAY INTO WEDNESDAY NIGHT.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT FIVE DAYS.

HINCKLEY RESERVOIR REMAINS ABOVE CAUTION STAGE…BUT LEVELS HAVE
CRESTED AND WILL CONTINUE TO GRADUALLY RECEDE THROUGH THE UPCOMING
WEEK.

COLD AND DRY WEATHER WILL PERSIST TONIGHT THROUGH MOST OF TUESDAY
NIGHT.

A WEAK STORM SYSTEM APPROACHING FROM THE GREAT LAKES WILL BRING
SOME SNOW AND RAIN SHOWERS TO THE REGION WEDNESDAY INTO EARLY
THURSDAY. TOTAL QPF APPEARS TO REMAIN LIGHT WITH THIS SYSTEM…AS
LIQUID EQUIVALENT AMOUNTS WILL RANGE FROM A TENTH TO A QUARTER OF
AN INCH.

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…FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY
EVENING FOR CTZ001-013.
NY…FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY
EVENING FOR NYZ032-033-038>043-047>054-058>061-063>066-
082>084.
MA…FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY
EVENING FOR MAZ001-025.
VT…FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY
EVENING FOR VTZ013>015.

&&

$$
SYNOPSIS…WASULA
NEAR TERM…IAA/WASULA
SHORT TERM…WASULA
LONG TERM…11
AVIATION…IAA
FIRE WEATHER…WASULA
HYDROLOGY…KL/WASULA

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