January 10, 2014 Forecast Discussion

000
FXUS61 KALY 101026
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
526 AM EST FRI JAN 10 2014

.SYNOPSIS…
A PERIOD OF LIGHT SNOW WILL OCCUR THIS MORNING AS A WEAK DISTURBANCE
IN THE UPPER LEVELS OF THE ATMOSPHERE APPROACHES AND MOVES ACROSS
THE REGION. AT THE SURFACE…HIGH PRESSURE WILL CONTINUE TO SHIFT
EASTWARD AND OFFSHORE TODAY. A POWERFUL STORM SYSTEM WILL MOVE
ACROSS THE REGION SATURDAY WITH VERY MILD AIR BEING USHERED IN AS
THE SYSTEM APPROACHES. SOME MIXED WINTRY PRECIPITATION IS POSSIBLE
LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING…THEN RAIN IS
EXPECTED INTO SATURDAY NIGHT. THE RAIN MAY BE HEAVY AT TIMES DURING
THE AFTERNOON INTO THE EVENING HOURS.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
LIGHT WARM ADVECTION SNOW HAS OVERSPREAD MUCH OF FORECAST AREA AHEAD
OF APPROACHING WEAK SHORT WAVE TROUGH. THE SNOW WILL CONTINUE
THROUGH MUCH OF THE MORNING COMMUTE TIME. ACCUMULATIONS WILL BE
LIGHT LESS THAN AN INCH. HOWEVER WITH THE GROUND SO COLD FROM RECENT
DAYS THE SNOW WILL LIKELY LEAD TO SOME SLIPPERY TRAVEL CONDITIONS.
HAVE ISSUED A SPECIAL WEATHER STATEMENT TO ADDRESS THIS THREAT.
CHANCES FOR SNOW WILL DECREASE RAPIDLY ONCE THE SHORT WAVE MOVES OFF
TO THE EAST THIS AFTERNOON.

AT THE SURFACE THE HIGH PRESSURE WILL CONTINUE TO SHIFT EASTWARD AND
OFFSHORE TODAY ALLOWING A SOUTHERLY RETURN FLOW TO DEVELOP. THUS
TEMPERATURES WILL CONTINUE TO MODERATE. SEASONAL READINGS ARE
EXPECTED TODAY WITH HIGHS IN THE 30S WITH SOME 20S ACROSS THE HIGHER
TERRAIN OF THE SOUTHERN ADIRONDACKS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/…
HAVE ISSUED A FLOOD WATCH FOR SATURDAY AFTERNOON THROUGH SUNDAY
PRIMARY THREAT ICE JAM FLOODING.

MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE TRACK AND TIMING OF THE
LOW ACROSS THE GREAT LAKES REGION AND EASTERN CANADA OVER THE
WEEKEND AND WITH THE PASSAGE OF THE COLD FRONT ACROSS OUR AREA
SATURDAY EVENING. THE UPPER TROUGH AMPLIFIES AS IT SWINGS THROUGH
BECOMING NEGATIVELY TILTED AS IT CROSSES THE REGION. THE MODELS KEEP
THE SYSTEM PROGRESSIVE.

CHANCES FOR PRECIPITATION WILL BEGIN TO INCREASE LATE IN THE EVENING
WITH LIKELY POPS NOT EXPECTED UNTIL AROUND SUNRISE. INITIALLY
TEMPERATURES WILL DROP THIS EVENING BEFORE STABILIZING THEN RISE
LATE AT NIGHT AS SOUTHERLY FLOW INCREASES. THIS OPENS THE DOOR TO
THE THREAT FOR A PERIOD OF LIGHT FREEZING RAIN AND SLEET LATE
TONIGHT INTO EARLY SATURDAY MORNING. THE THE BEST CHANCES WILL BE
IN THE FAVORABLE AREAS FOR FREEZING RAIN IN THE UPPER HUDSON
VALLEY…PORTIONS OF THE SOUTHERN ADIRONDACKS AND CONNECTICUT
RIVER VALLEY IN SOUTHERN VERMONT. HOWEVER DO NOT HAVE CONFIDENCE
TO ISSUE ANY HEADLINES AT THIS TIME. WILL CONTINUE TO HIGHLIGHT
THREAT IN OUR HAZARDOUS WEATHER OUTLOOK.

RAIN IS EXPECTED EVERYWHERE BY MID MORNING…THE RAIN SHOULD COME
DOWN HEAVY AT TIMES DURING THE AFTERNOON INTO THE EVENING ESPECIALLY
TO THE SOUTH AND EAST OF THE CAPITAL DISTRICT. RAINFALL AMOUNTS OF
3/4 TO 1 INCH ARE EXPECTED FROM THE CAPITAL DISTRICT NORTH AND
WEST WITH 1 TO 2 INCHES TO THE SOUTH AND EAST.

THE RAIN WILL FALL ON FROZEN GROUND WHICH WILL QUICKLY BECOME RUNOFF
AND MAY CAUSE SOME STREET AND OR POOR DRAINAGE FLOODING OF LOW LYING
AREAS.

VERY MILD AIR WILL BE USHERED IN AS THE SYSTEM APPROACHES AS A
STRONG LOW LEVEL JET MOVES INTO THE REGION. TEMPERATURES SHOULD WARM
INTO THE UPPER 40S TO LOWER 50S. THIS WILL LEAD TO SOME SNOW MELT.

THE COMBINATION OF THE WARM TEMPERATURES AND RAINFALL MAY CAUSE ICE
MOVEMENT AND BREAK UP FOR ICE JAM CAUSING FLOODING ON SOME RIVERS
AND STREAMS. THE THREAT FOR ICE JAM FLOODING WILL BE GREATEST LATE
SATURDAY AFTERNOON INTO SUNDAY.

A STRONG LOW LEVEL JET…850 MB 50 TO 60 KNOTS…DEVELOPS AND MOVES
INTO THE REGION EARLY SATURDAY MORNING. THIS JET STRENGTHENS DURING
THE DAY TO OUR EAST ACROSS NEW ENGLAND. THE MODEL INDICATE THE 925
MB FLOW INCREASES UP 50 KNOTS UP THE HUDSON RIVER VALLEY…HOWEVER
WILL BE DIFFICULT TO MIX STRONGER WINDS DOWN TO THE SURFACE. WILL
BE BREEZY.

THE COLD FRONT WILL SWEEP THROUGH SATURDAY EVENING WITH THE SHARPENING
UPPER TROUGH SWINGING THROUGH ON SUNDAY. THE STEADY RAIN WILL TAPER
OFF WITH THE PASSAGE OF THE FRONT WITH RAIN AND SNOW SHOWERS THEN
EXPECTED AS THE UPPER TROUGH APPROACHES.

ABOVE NORMAL TEMPERATURES ARE EXPECTED SUNDAY WITH RIDGING BUILDING
IN AT THE SURFACE ESPECIALLY DURING THE AFTERNOON.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/…
THE EXTENDED FORECAST FEATURES A PROGRESSIVE UPPER LEVEL PATTERN
WITH THE MOST PROLIFIC WEATHER SYSTEM IMPACTING THE REGION TUESDAY
INTO WEDNESDAY.

THE EXTENDED OPENS WITH HIGH PRESSURE RIDGING IN FROM THE MID
ATLANTIC AND SOUTHEAST SUNDAY NIGHT WITH FAIR WEATHER INTO MONDAY.
TEMPS WILL ACTUALLY BE ABOVE NORMAL WITH RIDGING IN FROM OFF THE
ATLANTIC SEABOARD TO START THE WEEK. H850 TEMPS RISE TO +4C TO +7C
WITH LOWS ONLY IN THE MID AND U20S SUNDAY NIGHT AND HIGHS IN THE MID
AND U40S OVER THE VALLEYS AND HILLS…AND L40S OVER THE MTNS.

MONDAY NIGHT INTO TUESDAY…A PAIR OF DISTURBANCES MAY IMPACT THE
REGION WITH A NRN STREAM UPPER LEVEL TROUGH APPROACHING FROM THE
GREAT LAKES REGION…AND SE CANADA…WHILE A SRN STREAM DISTURBANCE
ROUNDS THE BASE OF THE LONGWAVE TROUGH OVER THE SOUTHEAST AND MID
ATLANTIC REGION. THE ECMWF/GFS/CAN GGEM ARE NOT IN AGREEMENT ON THE
IMPACTS OR THE EVOLUTION OF A PHASED SYSTEM BETWEEN THE NRN AND SRN
STREAMS. THE ECMWF IS THE MOST AGGRESSIVE BRINGING THE SRN STREAM
SYSTEM N/NE FROM TN VALLEY AND THE MID ATLANTIC REGION WITH A BOUT
OF MDT-HVY PCPN TUE TRANSITIONING TO PERHAPS SOME SNOW. THE GFS IS
UNPHASED WITH THE NRN STREAM SYSTEM BRINGING SOME SHOWERS WITH THE
COLD FRONT. THE CAN GGEM INDICATES A STRONG COASTAL SYSTEM WITH THE
SUBTROPICAL OR SRN STREAM JET WITH SOME OVER RUNNING LIGHT RAIN OR
SNOW IN THE DEFORMATION ZONE TUE. OUR FCST FOLLOWS CLOSELY THE WPC
GUIDANCE WITH A CHC OF RAIN OR SNOW SHOWERS MONDAY NIGHT…WITH THE
WARM FRONT TO THE NRN STREAM SYSTEM PASSING WELL TO THE NORTH…AND
A GOOD CHC OF SHOWERS ON TUESDAY AHEAD OF THE COLD FRONT WITH HIGHS
IN THE U30S OVER THE SRN DACKS TO LOWER TO M40S OVER THE REST OF THE
REGION.

TUESDAY NIGHT INTO WEDNESDAY…A BROAD H500 UPPER TROUGH ESTABLISHES
ITSELF OVER THE EAST COAST WITH A SERIES OF DISTURBANCES PIVOTING
AROUND IT. THERE COULD BE SOME LAKE EFFECT SNOW SHOWERS WEDNESDAY
MORNING BEFORE HIGH PRESSURE BUILDS IN DURING THE AFTERNOON. H850
TEMPS FALL BACK TO -10C TO -14C BY WED PM. THE MILD SPELL ENDS WITH
LOWS IN THE 20S TO L30S…AND HIGHS ON WED IN THE U20S TO U30S.

WED NIGHT INTO THURSDAY…HIGH PRESSURE BUILDS IN FROM THE OH VALLEY
OVER THE NORTHEAST WITH CLEARING SKIES AND COLD CONDITIONS. LOWS
WILL BE IN THE TEENS TO L20S. HIGHS ON THU WILL BE IN THE U20S TO
L30S FROM THE CAPITAL REGION NORTH AND WEST…AND M30S TO THE SOUTH
AND EAST.

OVERALL…TEMPS WILL STILL AVG ABOVE NORMAL IN THE LONG TERM WITH
PCPN NEAR NORMAL OR ABOVE NORMAL DEPENDING ON THE TUE SYSTEM.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/…
HIGH PRESSURE CONTINUES TO MOVE OFF THE NEW ENGLAND COAST THIS
MORNING…AS A WARM FRONT APPROACHES FROM THE OHIO VALLEY. AN UPPER
LEVEL DISTURBANCE AHEAD OF THIS WARM FRONT WILL BRING SOME LIGHT
SNOW TO ERN NY AND WRN NEW ENGLAND THIS MORNING INTO THE AFTERNOON.

CIGS WILL THICKEN AND LOWER QUICKLY PRIOR TO THE ONSET OF THE WARM
ADVECTION SNOWFALL. CIGS AND VSBYS WILL LOWER TO MVFR-IFR IN THE
SNOW. EXPECT THE LIGHT SNOW TO END IN THE 20-22Z TIME FRAME AND CIGS
AND VSBYS TO RISE BACK TO THE VFR RANGE.

ACCUMULATIONS WILL BE LIGHT…RANGING FROM A DUSTING TO AN INCH.

THE WARM FRONT WILL APPROACH FROM THE SOUTH FRI NIGHT WITH SOME
RAINFALL APPROACHING POU TOWARDS 04Z/SAT.

THE WINDS WILL BE LIGHT TO CALM THIS MORNING…AND THEN BE FROM THE
SOUTH AT 4-7 KTS DURING THE LATE MORNING AND AFTERNOON BEFORE
BECOMING LIGHT TO CALM OVERNIGHT.

OUTLOOK…
SAT NIGHT: HIGH OPERATIONAL IMPACT. BREEZY. DEFINITE RA.
SUN: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHRA…SHSN. SUN
NIGHT-MON: NO OPERATIONAL IMPACT. NO SIG WX.
MON NIGHT-TUE: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA…SHSN.

&&

.HYDROLOGY…
HAVE ISSUED A FLOOD WATCH FOR SATURDAY AFTERNOON THROUGH SUNDAY
PRIMARY THREAT ICE JAM FLOODING.

A POWERFUL STORM SYSTEM WILL MOVE ACROSS THE REGION SATURDAY WITH
VERY MILD AIR BEING USHERED IN AS THE SYSTEM APPROACHES WITH
TEMPERATURES RISING INTO THE UPPER 40S TO LOWER 50S. THIS WILL LEAD
TO SOME SNOW MELT. SOME MIXED WINTRY PRECIPITATION IS POSSIBLE LATE
FRIDAY NIGHT INTO EARLY SATURDAY MORNING…THEN RAIN IS EXPECTED
INTO SATURDAY NIGHT. THE RAIN MAY BE HEAVY AT TIMES DURING THE
AFTERNOON INTO THE EVENING HOURS. RAINFALL AMOUNTS OF THREE
QUARTERS OF AN INCH TO AN INCH ARE EXPECTED FROM THE CAPITAL
DISTRICT NORTH AND WEST WITH 1 TO 2 INCHES TO THE SOUTH AND EAST.

THE RAIN WILL FALL ON FROZEN GROUND WHICH WILL QUICKLY BECOME RUNOFF
AND MAY CAUSE SOME STREET AND OR POOR DRAINAGE FLOODING OF LOW LYING
AREAS. THE WARM TEMPERATURES COMBINED WITH THE RAINFALL MAY CAUSE
ICE MOVEMENT AND BREAK UP FOR ICE JAM FLOODING ON SOME RIVERS AND
STREAMS. THE THREAT FOR ICE JAM FLOODING WILL BE GREATEST LATE
SATURDAY AFTERNOON INTO SUNDAY.

DESPITE THE PASSAGE OF THE SYSTEM ABOVE NORMAL TEMPERATURES ARE
EXPECTED TO PERSIST THROUGH EARLY NEXT WEEK. NIGHTTIME TEMPERATURES
WILL FALL TO AROUND FREEZING OR BELOW. OUR NEXT BEST CHANCES FOR
WIDESPREAD PRECIPITATION WILL TUESDAY WITH SNOW AT NIGHT AND RAIN
DURING THE DAY.

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…FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON
FOR CTZ001-013.
NY…FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON
FOR NYZ032-033-038>043-047>054-058>061-063>066-082>084.
MA…FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON
FOR MAZ001-025.
VT…FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON
FOR VTZ013>015.

&&

$$
SYNOPSIS…IAA
NEAR TERM…IAA
SHORT TERM…IAA
LONG TERM…WASULA
AVIATION…WASULA
HYDROLOGY…IAA/WASULA

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