March 19, 2014 Forecast Discussion

000
FXUS61 KALY 200028
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
828 PM EDT WED MAR 19 2014

.SYNOPSIS…
LOW PRESSURE…PASSING TO THE NORTH OF OUR REGION…WILL BRING
PERIODS OF PRECIPITATION TO THE REGION. THE PRECIPITATION WILL BE
MAINLY RAIN FROM ALBANY SOUTH IN THE HUDSON VALLEY…A WINTRY MIX
ACROSS THE HIGHER TERRAIN…MOSTLY SNOW ACROSS THE ADIRONDACKS. LOW
PRESSURE WILL PASS TO OUR EAST TOMORROW BUT COLD AIR ALOFT WILL KEEP
THE ATMOSPHERE SOMEWHAT UNSTABLE. COLDER AIR MOVES IN AGAIN FOR
FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/…
AS OF 800 PM…SLEET MORE WIDESPREAD ACROSS THE REGION WHERE NO
ADVISORIES ARE IN AFFECT…SO HAVE CHANGED MANY AREAS FROM RAIN AND
A CHANCE OF SLEET…TO RAIN AND SLEET LIKELY AND INCLUDED A TENTH OF
AN INCH OF ACCUMULATION. THE EXCEPTION WAS THE MID HUDSON VALLEY AND
LITCHFIELD COUNTY. HAVE ALSO MADE SOME ADJUSTMENTS TO THE HOURLY
TEMP GRIDS IN ORDER TO REFLECT CURRENT CONDITIONS.

PREVIOUS DISCUSSION…
AS OF 430 PM EDT…SHOWERS OF MAINLY RAIN AND SNOW WERE BREAKING OUT
ACROSS MUCH OF OUR REGION. AS ASCENT INCREASES TO ISENTROPIC LIFT
ASSOCIATED WITH A WARM FRONT WELL TO THE SOUTH OF REGION…SHOWERS
WILL BLOSSOM IN A STEADY SHIELD OF PRECIPITATION…AT LEAST FOR
AWHILE THIS EVENING.

LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL MOVE NORTH OF OUR
REGION TONIGHT…BUT A SECONDARY WAVE WILL TRY TO GET GOING ALONG
THE TRIPLE POINT (WHERE THE WARM FRONT MEETS THE COLD FRONT) OVER
THE JERSEY COAST. THIS WILL ENHANCE PRECIPITATION A LITTLE IN OUR
SOUTHERN ZONES…WHILE A SOUTH TO SOUTHWEST FLOW WILL ENHANCE
PRECIPITATION A LITTLE OVER THE ADIRONDACKS.

TEMPERATURES WERE ABOVE FREEZING FROM ABOUT GLENS FALLS SOUTHWARD IN
THE HUDSON VALLEY…WHILE CLOSER TO FREEZING (AND IN SOME CASES)
BELOW FREEZING ACROSS THE HIGHER TERRAIN AND EVEN INTO THE MOHAWK
VALLEY. WET BULBING OF THE PRECIPITATION (COOLING TEMPERATURES DOWN
DUE TO LARGE DEWPOINT DEPRESSION) WILL LIKELY COOL TEMPERATURES VERY
CLOSE TO FREEZING THIS EVENING…BUT WITH WARM AIR ADVECTION
ALOFT…TEMPERATURES SHOULD PRETTY MUCH LEVEL OUT AFTER
MIDNIGHT…AND FROM ALBANY SOUTHWARD…MIGHT EVEN RISE A DEGREE OR
TWO INTO THE EARLY PORTION OF THE OVERNIGHT.

P-TYPE WILL BE A CHALLENGE WITH THIS SYSTEM…MAINLY NORTH OF ALBANY
AND THE ELEVATED AREAS. FROM ALBANY SOUTHWARD…IT LOOKS TO BE
MOSTLY RAIN…BUT WE HAVE ALREADY HAD A LITTLE SLEET WITH INITIAL
INSTALLMENT (WITH NO ACCUMULATION). WE EXPECT NO ACCUMULATION FROM
ALBANY SOUTHWARD…EVEN IF A LITTLE SLEET FALLS.

HOWEVER…FURTHER NORTH…TEMPERATURES LOOK TO HIT FREEZING OR A
COUPLE DEGREES LOWER. THEREFORE…WE DID HOIST AN ADVISORY THERE (AS
WELL AS MOST OF THE ELEVATED TERRAIN). MUCH OF THIS IS DUE TO THE
FACT THERE COULD BE SOME FREEZING RAIN (ASSOCIATED WITH A WARM NOSE
ALOFT) THAT MIGHT EVEN BRIEFLY PUNCH INTO THE SOUTHERN ADIRONDACKS.
HOWEVER…ACROSS THE ADIRONDACKS THE PRIMARY PRECIPITATION TYPE
LOOKS TO BE SNOW (MIXED WITH SLEET AND A LITTLE FREEZING
RAIN…MAINLY SOUTH OF ROUTE 8). LOOK FOR 2-6 INCHES OF SNOWFALL
THROUGH THE MORNING DRIVE IN THIS AREA ALONG WITH SLIPPERY
ROADS.

THE REST OF THE ADVISORY AREAS (LAKE GEORGE SARATOGA…EAST INTO
SOUTHERN VERMONT…AS WELL AS THE CATSKILLS AND MOHAWK VALLEY) WILL
BE A HODGE PODGE OF SLEET…FREEZING RAIN AND PERHAPS EVEN A LITTLE
SNOW. SNOW WILL NOT BE THE MAIN ISSUES…BUT AREAS LIKE FULTON
COUNTY COULD GET UP TO 2 INCHES OF SNOW SLEET AS PORTIONS OF THE
SOUTHERN GREENS. OTHER REMAINING AREAS IN THE ADVISORY WILL LIKELY
SEE LITTLE OR NO ACCUMULATION OF FROZEN PRECIPITATION…BUT COULD
SEE UP TO A TENTH OF TWO OF ICE ACCRETION (FREEZING PRECIPITATION).
MOST OF THE VALLEY AREAS SHOULD SEE LESS THAN A TENTH OF AN INCH OF
ICE…BUT COULD STILL HAVE SOME VERY SLICK ROAD CONDITIONS.

AS USUAL…SURFACE TEMPERATURES WILL PLAY A KEY ROLE IN THE ULTIMATE
OUTCOME OF THIS EVENT. A DEGREE OR TWO OF ERROR WOULD MEAN THIS
ADVISORY MIGHT HAVE TO BE A READJUSTED A BIT. STAY TUNED.

ONE LAST THING. SHOWALTER INDICES (THE DIFFERENCE IN TEMPERATURE
BETWEEN THE H850 LEVEL AND H500 LEVEL) DROP TO BELOW ZERO THIS
EVENING SOUTH OF ALBANY. THE STORMS PREDICTION CENTER HAD GENERAL
THUNDER UP TO ALBANY). FOR NOW WILL ONLY MENTION A SLIGHT CHANCE OF
THUNDERSTORMS THIS EVENING ACROSS THE MID HUDSON VALLEY AND
LITCHFIELD COUNTY. IF THESE WERE TO TAKE PLACE…THEY WOULD INCREASE
THE CHANCE OF SLEET (REALLY GRAUPEL) BUT FOR NOW JUST HAVE THE
CHANCE OF SLEET DOWN THERE AS WELL.

OVERNIGHT LOWS WILL ULTIMATELY RANGE FROM THE MID 20S TO LOWER 30S.
WE DO HAVE TEMPERATURES GOING AT OR BELOW FREEZING IN THE MID HUDSON
VALLEY…BUT THAT IS MAINLY BECAUSE WE MIGHT ACTUALLY SEE SOME
PARTIAL CLEARING AND LIGHT WIND BEFORE DAYBREAK…WHICH COULD ALLOW
THOSE TEMPERATURES TUMBLE…BUT LIKELY AFTER THE PRECIPITATION IS
OVER.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/…

PRECIPITATION WILL END IN MOST AREAS TOMORROW MORNING. THE ONE
EXCEPTION MIGHT BE THE ADIRONDACKS AND SOUTHERN GREEN. AS COLD FRONT
WILL SWEEP ACROSS THE REGION EARLY ON. AN UPSLOPE WIND WILL
INITIALLY ALLOW FOR SOME POSSIBLE ADDITIONAL SHOWERS OF SNOW ACROSS
THE ADIRONDACKS.

LATER THURSDAY…AS A COLD POCKET OF AIR MOVES OVERHEAD…ASSOCIATED
WITH THE UPPER LOW PORTION OF THE SYSTEM…INSTABILITY WILL LIKELY
ALLOW FOR INCREASES CLOUDS AGAIN EVERYWHERE. INSTABILITY SHOWERS OF
RAIN…SNOW AND GRAUPEL WILL LIKELY INCREASES…MOST NUMEROUS IN THE
ADIRONDACK PARK…LESS NUMEROUS ON THE HUDSON VALLEY SOUTH OF
ALBANY. TEMPERATURES SHOULD BE INTO THE 40S ACROSS THE HUDSON VALLEY
(TOUCHING 50 DOWN SOUTH) SO ANY SHOWER SHOULD BE RAIN.
HOWEVER…ACROSS THE HIGHER TERRAIN…A MIX OF GRAUPEL AND SNOW WILL
ENSUE AS TEMPERATURES HOLD MAINLY IN THE 30S…WITH MORE
ACCUMULATING SNOW POSSIBLE ACROSS THE ADIRONDACK PARK (WHERE HIGHS
WILL BE IN THE LOWER TO MID 30S).

AS THE UPPER AIR LOW PULLS AWAY DURING THE AFTERNOON…THE WIND WILL
PICK UP AS WELL EVERYWHERE FROM A WEST OR NORTHWESTERLY
DIRECTION…GUSTING TO 25 MPH OR BETTER (ACROSS THE HIGHER
TERRAIN/MOHAWK VALLEY AND CAPITAL DISTRICT).

THURSDAY NIGHT…LEFTOVER LAKE ENHANCED UPSLOPE SNOW SHOWERS COULD
PERSIST FOR AWHILE ESPECIALLY ACROSS THE ADIRONDACKS…AND EVEN
SOUTHERN GREENS. IT SHOULD BE DRY EVERYWHERE ELSE. A BRISK
EVENING…BUT THE WINDS WILL DIMINISH A LITTLE OVERNIGHT…EXCEPT IN
THOSE WIND PRONE AREAS (HIGHER TERRAIN/MOHAWK VALLEY/CAPITAL
DISTRICT). TEMPERATURES WILL GENERALLY TUMBLE BACK INTO THE
20S…COLDEST OVER THE HIGHER TERRAIN WHERE THEY WILL BE CLOSER TO
20 DEGREES.

FRIDAY…WILL START OUT BREEZY WITH ANY LEFTOVER SNOW SHOWERS ENDING
ACROSS THE ADIRONDACKS AS HIGHER PRESSURE SETTLES IN. THIS SHOULD
ALLOW FOR THE BREEZE TO ABATE BUT PROBABLY NOT EVERYWHERE UNTIL LATE
IN THE DAY. THERE WILL BE INCREASING SUNSHINE BUT TEMPERATURES WILL
CONTINUE TO RUN CHILLIER THAN NORMAL (AS THEY HAVE BEEN THIS ENTIRE
MONTH). LOOK FOR HIGHS 40-45 ACROSS MOST OF THE HUDSON VALLEY WITH
SOME UPPER 40S TO NEAR 50 IN THE SOUTHERN MID HUDSON VALLEY AND
LOWER LITCHFIELD COUNTY). HIGHS WILL ONLY BE IN THE MID TO UPPER 30S
ACROSS THE MOHAWK VALLEY…SOUTHERN GREENS…CATSKILLS AND
BERKSHIRES. HIGHS WILL ONLY AROUND 30 ACROSS THE ADIRONDACKS.

FRIDAY NIGHT…A CLIPPER WILL MOVE QUICKLY SOUTHWARD FROM THE ARROW
HEAD OF MINNESOTA…AND APPROACH OUR REGION LATE AT NIGHT. IT LOOKS
TO TRACK ACROSS THE ADIRONDACKS SO ONCE AGAIN…THEY WILL HAVE THE
BEST CHANCE FOR MORE SNOW. IT NOW APPEARS ENOUGH WARM AIR ALOFT
MIGHT ALLOW FOR ANY PRECIPITATION FURTHER SOUTH TO MIX OF SNOW SLEET
AND POSSIBLY EVEN FREEZING RAIN. FOR NOW…DUE TO HIGH
UNCERTAINTY…WE LEFT OUT ANY FREEZING RAIN…BUT IT IS POSSIBLE.
PRECIPITATION AMOUNTS LOOK LIGHT BUT COULD STILL CAUSE SOME SLICK
ROADWAYS BY DAYBREAK ESPECIALLY NORTH. LOWS WILL BE IN THE LOWER 30S
SOUTH OF ALBANY IN THE HUDSON VALLEY…GENERALLY 20S FURTHER
NORTH…UPPER 20S LOCALLY IN THE CAPITAL DISTRICT.

SATURDAY…THE CLIPPER MOVES AWAY…BUT THE UPPER AIR LOW WILL LAG A
LITTLE BEHIND. HAVE LOWERED POPS TO HIGH AND MID CHANCE FROM ALBANY
SOUTHWARD AS MOISTURE LOOKS LIMITED…BUT CONTINUE WITH LIKELY POPS
FOR SNOW (OR A WINTRY MIX) ACROSS AREAS NORTH OF ALBANY…MAINLY THE
HIGHER TERRAIN. IT WILL TURN BREEZY ONE AGAIN WITH HIGHS RANGING
FROM THE LOWER 50S FROM POUGHKEEPSIE TO LOWER LITCHFIELD…40S
ACROSS THE REMAINDER OF THE HUDSON VALLEY AND EVENING INTO THE
CATSKILLS. FURTHER NORTH…30S WILL BE MAINLY CONFINED TO THE
ADIRONDACKS AND SOUTHERN GREENS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/…
A COLD AND UNSETTLED NORTHWEST FLOW OF AIR FORECAST TO BE OVER THE
REGION SATURDAY NIGHT INTO SUNDAY…WITH SLIGHT CHANCE TO LOW CHANCE
POPS FORECAST ACROSS THE REGION…AND THE HIGHEST POPS OVER TERRAIN
AREAS AND ACROSS THE NORTHWEST PART OF THE FORECAST AREA. BY SUNDAY
NIGHT ANOTHER LARGE AND COLD HIGH PRESSURE SYSTEM WILL BUILD IN
FROM THE GREAT LAKES AREA…AND THIS WILL RESULT IN DRY CONDITIONS
AND LESS CLOUD COVER. THE CENTER OF THE HIGH WILL MOVE OFF THE NEW
ENGLAND COAST BY TUESDAY MORNING WITH MOISTURE ACROSS THE REGION
INCREASING MONDAY NIGHT AND TUESDAY. IT WILL REMAIN DRY THROUGH
MONDAY NIGHT…BUT HAVE INTRODUCED A 30 PERCENT CHANCE OF SNOW
ACROSS THE REGION ON TUESDAY AS OVERUNNING MOISTURE SURGES INTO THE
REGION. THE WEATHER FOR TUESDAY NIGHT AND WEDNESDAY WILL DEPEND ON
THE EVOLUTION OF A STORM SYSTEM THAT WILL BE MOVING OFF THE
SOUTHEAST COAST DURING THAT TIME. MEDIUM RANGE MODELS HAVE BEEN
GOING BACK AND FORTH BETWEEN A MONSTER STORM DEVELOPING OFF THE EAST
COAST…AND AN INSIGNIFICANT SYSTEM. IN ADDITION…MOST MODEL RUNS
KEEP THE WORST OF WHATEVER HAPPENS TO THE SOUTH OF THE ALBANY
FORECAST AREA. FOR NOW WILL SIMPLY FORECAST A 40 PERCENT CHANCE OF
SNOW DURING THE TUESDAY NIGHT/WEDNESDAY PERIOD.

TEMPS WILL BE BELOW NORMAL DURING THIS PERIOD. LOWS SATURDAY NIGHT
WILL BE IN THE MID TEENS TO THE 20S. HIGHS SUNDAY IN THE UPPER 20S
TO LOWER 40S. LOWS SUNDAY AND MONDAY NIGHTS RANGING FROM A FEW
DEGREES BELOW ZERO TO THE MID TEENS. HIGHS MONDAY IN THE 20S TO
LOWER 30S. HIGHS TUESDAY IN THE UPPER 20S AND 30S. LOWS MONDAY NIGHT
IN THE TEENS AND LOWER 20S. HIGHS WEDNESDAY IN THE UPPER 20S AND
30S.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/…
PCPN NOW OCCURRING ACROSS ALL THE TAF SITES WITH CONDITIONS
GENERALLY VFR TO MVFR. EXPECT THAT CONDITIONS WILL CONTINUE TO LOWER
WITH MOST OF THE NIGHT FORECAST TO BE MVFR TO IFR. PCPN TYPES WILL
BE RAIN AT KPOU. MAINLY RAIN WITH OCCASIONAL PL AT KALB/KPSF…AND
SNOW/PL/RAIN AT KGFL. SHORTLY AFTER SUNRISE ON THURSDAY THE FRONTAL
BOUNDARY ASSOCIATED WITH THE SURFACE LOW MOVING EAST ACROSS SOUTHERN
CANADA WILL MOVE ACROSS THE TAF SITES (GENERALLY BETWEEN 12Z AND
14Z). ONCE THE FRONT MOVES THROUGH HAVE FORECAST CONDITIONS AT THE
TAF SITES TO QUICKLY IMPROVE TO VFR WITH THE EXCEPTION OF KPSF WHERE
MVFR CIGS WILL LIKELY HANG ON UNTIL EARLY AFTN.

WIND WILL BE EAST TO SOUTHEAST TONIGHT (GENERALLY LESS THAN 10 KTS).
LATE TONIGHT THE WINDS WILL GRADUALLY BECOME SOUTHERLY OR SOUTHWEST.
BEHIND THE FRONTAL PASSAGE ON THURSDAY WINDS WILL BECOME WESTERLY
AND INCREASE TO 10 TO 14 KTS WITH GUSTS OF 20 KTS OR MORE.

OUTLOOK…
THU NIGHT-FRI: LOW OPERATIONAL IMPACT. BREEZY.
FRI NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF A WINTRY MIX.
SAT: MODERATE OPERATIONAL IMPACT. CHC RA…SN.
SAT NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUN: LOW OPERATIONAL IMPACT. BREEZY. SLIGHT CHANCE OF SHRA…SHSN.
SUN NIGHT-MON…NO OPERATIONAL IMPACT. NO SIG WX.
&&

.FIRE WEATHER…
NO FIRE WEATHER RELATED CONCERNS ARE ANTICIPATED…AS MUCH OF THE
AREA HAS EITHER SNOW COVER AND OR FROZEN GROUND AND TEMPERATURES
WILL CONTINUE TO BE GENERALLY BELOW NORMAL WELL INTO NEXT WEEK.

THERE WILL ALSO BE PRECIPITATION TONIGHT AND AGAIN POSSIBLY FRIDAY
NIGHT.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE ANTICIPATED THROUGH THE NEXT 5 DAYS.

THE PRECIPITATION TONIGHT WILL BE MAINLY RAIN FROM ALBANY SOUTH…A
MIX ACROSS THE HIGHER TERRAIN…AND MOSTLY SNOW ACROSS THE
ADIRONDACKS. PRECIPITATION AMOUNTS LOOK TO BE AROUND A QUARTER INCH
LOCALLY IN THE CAPITAL DISTRICT…CLOSER TO HALF AN INCH ALL AREAS
SURROUNDING THE CAPITAL REGION.

MAINLY DRY ON THURSDAY(OUTSIDE OF SOME UPSLOPE SNOW SHOWERS) AND
PERHAPS A FEW LIGHTER SCATTERED SHOWERS IN VALLEY LOCATIONS. DRY
FRIDAY WITH THE NEXT CHANCE OF SNOW OR MIXED PRECIPITATION FRIDAY
NIGHT INTO SATURDAY. AMOUNTS LOOK LIGHT.

NO RESPONSES ARE ANTICIPATED ON THE RIVERS AND STREAMS. ICE IS NOW
SLOWLY BREAKING UP ON THE RIVERS AND STREAMS FROM ALBANY
SOUTHWARD…BUT HOLDS TOUGH FURTHER NORTH DUE TO COLDER TEMPERATURES
AND SNOW COVER.

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 10 AM EDT THURSDAY FOR NYZ032-
033-038>043-047-048-051-054-058-061-063-082>084.
MA…WINTER WEATHER ADVISORY UNTIL 10 AM EDT THURSDAY FOR MAZ001-
025.
VT…WINTER WEATHER ADVISORY UNTIL 10 AM EDT THURSDAY FOR
VTZ013>015.

&&

$$
SYNOPSIS…HWJIV
NEAR TERM…GJM/HWJIV
SHORT TERM…HWJIV
LONG TERM…GJM
AVIATION…GJM
FIRE WEATHER…HWJIV/JPV
HYDROLOGY…HWJIV

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