March 2, 2014 Forecast Discussion

000
FXUS61 KALY 021756
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1250 PM EST SUN MAR 2 2014

.SYNOPSIS…
THE RETURN OF ANOTHER ARCTIC AIR MASS WILL SETTLE INTO THE REGION
TODAY WITH SOME LIGHT SNOW OR FLURRIES. ACCUMULATIONS WILL BE
RATHER LIGHT AND MAINLY CONFINED ACROSS THE HIGHER TERRAIN. MORE
BITTERLY COLD AIR IS EXPECTED APPROACHING THE MIDDLE OF THE WEEK AS
A LARGE ARCTIC HIGH PRESSURE SYSTEM BUILDS IN ACROSS EASTERN NEW
YORK AND WESTERN NEW ENGLAND.

&&

.NEAR TERM /THROUGH TONIGHT/…
AS OF 945 AM EST…SNOW SHOWERS BEHIND THE PASSING COLD FRONT
CONTINUE TO WEAKEN AS THEY MOVE EAST ACROSS THE MOHAWK VALLEY INTO
THE IMMEDIATE CAPITAL REGION. LOCAL MODEL RUNS SHOW REFLECTIVITY
VALUES FURTHER SOUTH AND EAST OUT OF OUR COUNTY WARNING AREA
ASSOCIATED WITH THE BAROCLINIC ZONE AS WE GO THROUGH THE AFTERNOON
HOURS. FOR THIS UPDATE WE HAVE LOWERED SNOWFALL EXPECTATIONS ALONG
WITH POPS ESPECIALLY IN OUR NORTHERN AND WESTERN AREAS WHERE THE
COLD FRONT HAS MADE ITS WAY WELL SOUTH AND EAST OF THOSE AREAS.
TEMPERATURES HAVE BEEN MODIFIED SLIGHTLY ACROSS THE MID HUDSON
VALLEY WELL SOUTH OF THE IMMEDIATE CAPITAL REGION WHERE THE FRONT
IS SLOWLY PROGRESSING TOWARD. LATEST OBSERVATIONS SHOWED
TEMPERATURES IN THE MID HUDSON VALLEY NEAR NW CONNECTICUT IN THE
LOWER 30S WHICH SHOULD HOLD FOR THE NEXT FEW HOURS BEFORE
TEMPERATURES BEGIN TO DROP THROUGH THE 20S HERE AS WELL AS WE GO
INTO THE AFTERNOON HOURS.

TONIGHT…THE ARCTIC BOUNDARY WILL LIKELY SLOW THE FORWARD
PROGRESS ALONG THE I80 CORRIDOR AS THE SURFACE FEATURES PARALLEL
THE UPPER LEVEL FLOW. FURTHERMORE…UPPER LEVEL JET ACROSS UPSTATE
NY IS FORECAST TO INTENSIFY >170KTS WITH ENTRANCE REGION DYNAMICS
ENHANCING LIFT ACROSS PA/NJ. FGEN FORCING IS FORECAST TO INCREASE
A BIT ACROSS OUR SOUTHERN ZONES THAT COINCIDES WITH DRIER AIR
ADVECTING IN FROM THE NORTH. SO THE SNOW ACCUMULATIONS ACROSS
THESE AREAS ARE EXPECTED TO BE LESS THAN 4 INCHES WITH THE
REMAINDER OF THE REGION SEEING COLDER AND DRIER CONDITIONS.
HOWEVER…ONE EXCEPTION TO THIS WILL BE DOWNWIND OF LAKE
CHAMPLAIN. MESOSCALE MODELS AND BUFR PROFILES ACROSS KGFL SUGGEST
WITH THE COLD ADVECTION ALONG WITH A NORTHERLY WIND DOWN THE
VALLEY AND ANY MOISTURE FLUX OFF THE LAKE COULD BRING SOME LAKE
SNOW SHOWERS/FLURRIES INTO THE LAKE GEORGE/GLENS FALLS REGION
THROUGH THIS EVENING AS WE WILL RETAIN CHC-SCT POPS TO ACCOUNT FOR
THIS POTENTIAL. OTHERWISE…SLOWLY CLEARING SKIES FROM NORTH TO
SOUTH AS SURFACE TEMPS DROP BACK WELL DOWN INTO THE SINGLE DIGITS
TO BELOW ZERO ACROSS THE HIGHER TERRAIN WHERE THE DACKS H850 TEMPS
ARE PROGGED TO BE AT OR BELOW -20C. WINDS MAY BE CLOSE FOR WIND
CHILL THRESHOLDS ACROSS THE DACKS BUT PER COLLABORATION…NO
HEADLINES AT THIS TIME.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/…
ARCTIC AIRMASS SETTLES ACROSS THE REGION MONDAY AS HIGH PRESSURE
BUILDS IN FROM THE WEST. PWATS ARE EXPECTED TO REMAIN BELOW ONE
TENTH OF AN INCH SO A VERY DRY AIRMASS TO BRING A MAINLY SUNNY
SKY. DESPITE THE EARLY MARCH SUN ANGLE…HIGH TEMPERATURES WILL
STRUGGLE TO REACH 20F FOR VALLEY LOCATIONS AND MAINLY TEENS AND
SINGLE DIGITS FOR THE HIGHER TERRAIN. OUR NORMAL HIGH FOR THIS
TIME OF THE YEAR ARE WELL INTO THE 30S TO LOWER 40S FOR THE MID
HUDSON VALLEY.

MONDAY NIGHT COULD BE QUITE COLD WITH INITIALLY CLEAR SKIES AND
LIGHT WINDS WITH SNOW COVER TO RESULT IN BELOW ZERO READINGS FOR
MOST OF THE REGION. SOME HIGHER LEVEL CLOUD COVER IS EXPECTED TO
ADVECT INTO THE REGION FROM THE WEST OVERNIGHT BUT LIKELY THE
TEMPS WILL HAVE ALREADY DROPPED.

THE AFOREMENTIONED INCREASE IN CLOUD COVER WILL BE FROM THE SYSTEM
MOVING IN ACROSS THE PACIFIC NORTHWEST AND TRACKING ACROSS THE
NORTHERN TIER OF THE COUNTRY AND GREAT LAKES REGION. AS WAS THE
CASE WITH OUR CURRENT SYSTEM…THE UPPER FLOW REMAINS QUITE
CONFLUENT SO ANY PRECIP ACCOMPANYING THIS FEATURE WILL REMAIN
LIGHT. WE WILL INCREASE INTO LOW CHANCE POPS AS HIGH TEMPERATURES
CLIMB INTO THE 20S FOR VALLEY LOCATIONS AND TEENS ELSEWHERE AS
THOSE H850 TEMPS REMAIN INTO THE NEGATIVE TEENS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/…
A REINFORCING SHOT OF ARCTIC AIR WILL BE MOVING TOWARDS THE REGION
AT THE START OF THE EXTENDED PERIOD…AS A MOISTURE STARVED FRONTAL
BOUNDARY MOVES IN THE FAST NORTHERN STREAM TOWARDS THE AREA. SOME
ISOLATED SNOW SHOWERS AND FLURRIES WILL ACCOMPANY THE BOUNDARY
BETWEEN TUESDAY NIGHT AND WEDNESDAY AS IT CROSSES THE REGION FROM
WEST TO EAST…BUT ANY SNOW ACCUMULATION WILL BE RATHER LIMITED FROM
THIS SYSTEM. BELOW NORMAL TEMPS WILL CONTINUE WITH MINS ON TUESDAY
NIGHT RANGING FROM -10 IN THE ADIRONDACKS TO +10 IN THE MID HUDSON
VALLEY. MAX TEMPS ON WED WILL GENERALLY BE IN THE TEENS TO MID 20S.

A STRONG AREA OF HIGH PRESSURE WILL PASS OVER THE AREA ON WEDNESDAY
NIGHT INTO THURSDAY. THIS WILL ALLOW FOR DRY WEATHER…WITH
CONTINUED BELOW NORMAL TEMPS. MINS WED NIGHT WILL ONCE AGAIN BE IN
THE SINGLE DIGITS /BELOW ZERO OVER THE HIGH TERRAIN/. MAX TEMPS ON
THURSDAY WILL BE A LITTLE WARMER…AS THE WIND SWITCHES TO A
SOUTHERLY DIRECTION…WITH MID TO UPPER 20S IN MANY AREAS.

LATE IN THE WEEK…A DISTURBANCE IN THE SOUTHERN STREAM WILL ALLOW A
STORM TO DEVELOP OFF THE SOUTHEAST COAST. THE LATEST MODEL
GUIDANCE…INCLUDING THE 00Z GEFS…SEEM TO SUGGEST THIS SYSTEM WILL
REMAIN FAR ENOUGH SOUTH AND EAST OF THE AREA TO PREVENT ANY IMPACT
ON OUR WEATHER. HOWEVER…SINCE A FEW ENSEMBLE MEMBER DO SHOW SOME
PRECIP…AND SOME RECENT MODEL RUNS HAVE SHOWN A CLOSER
APPROACH…WE WILL CONTINUE TO GO WITH SLIGHT CHC TO LOW CHC
POPS…ESP FOR OUR EASTERN AREAS…FOR FRIDAY NIGHT INTO SATURDAY.
IN ADDITION…A PASSING WEAK NORTHERN STREAM SYSTEM MAY ALLOW FOR
SOME SNOW SHOWERS OVER THE WEEKEND AS WELL. TEMPS WILL BE MODERATING
FROM THE RECENT ARCTIC COLD…WITH MAX TEMPS ON FRI/SAT IN THE 30S
/EVEN SOME LOW 40S FOR FAR SOUTHERN AREAS/ WITH MINS IN THE 20S
/SOME TEENS OVER THE HIGH TERRAIN/.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/…
MAINLY VFR FLYING CONDITIONS EXPECTED THROUGH THE TAF PERIOD.

AN ARCTIC FRONT HAS SWEPT THROUGH ALL THE TERMINALS. IN ITS WAKE
WERE A FEW LINGERING SNOW SHOWERS AND POCKETS OF MVFR CLOUDS. AS
DRIER AIR WORKS IN…ANY SNOW SHOWERS WILL DIMINISH AND MVFR CLOUDS
AS WELL. THIS PROCESS WILL WORK FROM NORTH TO SOUTH…SO IT WILL
ACTUALLY TAKE UNTIL MUCH OF THE NIGHT BEFORE THE POSSIBILITY OF SNOW
SHOWERS COMPLETELY CAN BE RULED AT KPOU…WHILE AT KGFL AND
KALB…IT SHOULD HAPPEN BY 00Z. KPSF WILL BE IN BETWEEN…WITH ALL
SNOW SHOWER ACTIVITY EXPECTED TO END BY 06Z.

AT WORST…THE SNOW SHOWERS COULD BRIEFLY REDUCE VISIBILITY TO THE
IFR/MVFR RANGE AS THEY DID AT KGFL SHORTLY BEFORE NOON.
HOWEVER…THE THREAT OF PROLONGED MVFR AND ESPECIALLY IFR IS VERY
LOW (LESS THAN 25 PERCENT) SO AGAIN…MAINLY VFR FLYING CONDITIONS
ARE EXPECTED.

A WEST TO NORTHWEST WIND WILL PREVAIL THIS
AFTERNOON…5-10KTS…GUSTING TO 20KTS MAINLY AT KPSF AND KALB. THE
GUSTINESS IS EXPECTED TO DIMINISH AFTER DARK.

GOOD FLYING CONDITIONS EXPECTED ON MONDAY. ANY CIGS WILL BE OF THE
HIGH AND MID LEVEL VARIETY WITH UNRESTRICTED VISIBILITIES AS LONG AS
SNOW FROM A DISTURBANCE REMAINS SUPPRESSED TO THE SOUTH. WE HAVE
CONFIDENCE THIS WILL BE THE CASE.

A NORTH TO NORTHWEST WIND WILL CONTINUE 5-10KTS ON MONDAY.

OUTLOOK…
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY-WEDNESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
WEDNESDAY NIGHT-FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.HYDROLOGY…
NO WIDESPREAD HYDRO IMPACTS ARE EXPECTED ON THE MAIN STEM RIVERS
THE NEXT 5 DAYS. AN ARCTIC AIR MASS WILL REMAIN ACROSS THE HYDRO
SERVICE AREA INTO THE MIDDLE OF THE FIRST WEEK OF MARCH. THIS WILL
ALLOW ICE TO REFORM…THICKEN…AND STRENGTHEN ON AREA RIVERS AND
LAKES THROUGH MOST OF THE UPCOMING WEEK.

LIGHT PRECIPITATION IN THE FORM OF LIGHT SNOW/SNOW SHOWERS ARE
EXPECTED THROUGH THE TODAY…ESPECIALLY SOUTH OF ALBANY…AND
AGAIN TOWARD THE MIDDLE OF THE WEEK ACROSS MOST OF THE REGION.

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…BGM
NEAR TERM…LFM/BGM
SHORT TERM…BGM
LONG TERM…FRUGIS
AVIATION…HWJIV
HYDROLOGY…BGM

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