April 24, 2012 Forecast Discussion

000
FXUS61 KALY 242108
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
508 PM EDT TUE APR 24 2012

.SYNOPSIS…
A STRONG LOW PRESSURE SYSTEM WILL CONTINUE MOVING NORTHWARD INTO
EASTERN CANADA TONIGHT INTO WEDNESDAY. WEAK DISTURBANCES ROTATING
AROUND THIS LOW WILL KEEP COOL TEMPERATURES AND LOTS OF CLOUDS
AROUND THE REGION INTO WEDNESDAY…ALONG WITH THE POSSIBILITY OF
SOME SHOWERS OF RAIN AND WET SNOW…PARTICULARLY ACROSS HIGHER
TERRAIN. ANOTHER LOW PRESSURE SYSTEM APPROACHING FROM THE WEST
WILL BRING SHOWERS TO THE REGION THURSDAY AFTERNOON AND EVENING.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/…
AS OF 440 PM EDT…SOME BREAKS IN THE CLOUDS HAVE DEVELOPED WITHIN
THE HUDSON RIVER VALLEY…AS WEAK SUBSIDENCE IN THE WAKE OF A
PASSING SHORTWAVE…AND ALSO A DOWNSLOPING SSW FLOW OFF THE
CATSKILLS HELPS MIX SOME DRIER AIR DOWNWARD. SCATTERED TO NUMEROUS
SHOWERS OF RAIN…SNOW…AND GRAUPEL/SMALL HAIL/ CONTINUE TO
AFFECT THE WESTERN ADIRONDACKS AND MOHAWK VALLEY…WITH MORE
ISOLATED COVERAGE FURTHER S AND E INTO THE CATSKILLS AND SCHOHARIE
VALLEY REGIONS. THE AREAL COVERAGE OF THESE SHOWERS SHOULD
DECREASE A BIT THROUGH SUNSET…ALTHOUGH WILL MAINTAIN SOME SLIGHT
CHC POPS IN VALLEYS AND AREAS ACROSS WESTERN NEW ENGLAND TO
ACCOUNT FOR POSSIBILITY THAT SOME SHOWERS MAY PERSIST. ACROSS NW
AREAS…WILL MAINTAIN LIKELY POPS…AS NUMEROUS SHOWERS SHOULD
PERSIST WELL INTO THIS EVENING.

THE UPPER LEVEL TROUGH WILL GRADUALLY PIVOT EASTWARD LATER
TONIGHT. AN ATTENDANT SURFACE TROUGH WILL ALSO APPROACH FROM
CENTRAL NYS LATER TONIGHT. THIS MAY PROVIDE ENOUGH FORCING TO
PRODUCE ADDITIONAL SHOWERS OF RAIN AND SNOW OVERNIGHT…AGAIN WITH
THE BEST CHC ACROSS WESTERN AREAS.

TEMPS WILL BE EXTREMELY TRICKY OVERNIGHT…AND HAVE OVERALL LOW
CONFIDENCE IN FORECAST MINS. THE MAIN REASON FOR UNCERTAINTY WILL
BE THE POSSIBILITY OF BREAKS IN THE CLOUDS PERSISTING LONGER THAN
ANTICIPATED WITHIN THE HUDSON RIVER VALLEY REGION…WHERE AS
PREVIOUSLY MENTIONED…A LOW LEVEL SW FLOW FROM THE CATSKILLS MAY
TEND TO ALLOW CLOUDS TO BREAK UP…AT LEAST THROUGH MIDNIGHT. AS
THE AFOREMENTIONED SFC TROUGH SLOWLY MOVES E LATER TONIGHT…WINDS
MAY VEER MORE INTO THE SW TO W…WHICH MAY DISRUPT THIS
DOWNSLOPING AND ALLOW CLOUDS TO MORE EASILY SPREAD E INTO THE
HUDSON VALLEY REGION. FOR NOW…HAVE GENERALLY INDICATED MID TO
UPPER 30S IN MOST OF THE HUDSON RIVER VALLEY…MOHAWK VALLEY AND
WESTERN NEW ENGLAND REGION…HOWEVER SHOULD BREAKS PERSIST
LONGER…COLDER MINS WILL BE POSSIBLE…WHICH COULD LEAD TO AREAS
OF FROST BEFORE DAYBREAK WEDNESDAY. ACROSS HIGHER
ELEVATIONS ACROSS THE ADIRONDACKS…EXPECT MINS TO FALL INTO THE
UPPER 20S TO LOWER 30S.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/…
WEDNESDAY…THE UPPER LEVEL TROUGH AXIS…AND ASSOCIATED LOW/MID
LEVEL COLD POOL WILL PIVOT EASTWARD ACROSS THE REGION DURING THE
DAY. THIS SHOULD ONCE AGAIN ALLOW CLOUDS TO DEVELOP RAPIDLY IN
VALLEY REGIONS AFTER SOME BREAKS OF SUNSHINE. ALSO…ISOLATED TO
SCATTERED SHOWERS OF RAIN/SNOW/GRAUPEL WILL ONCE AGAIN
DEVELOP…WITH THE GREATEST FREQUENCY AND AREAL COVERAGE ACROSS NW
AREAS. THE SHOWERS SHOULD GENERALLY REMAIN LOW TOPPED…WITHOUT
ANY THUNDER. FORECAST SOUNDINGS DEPICT AFTERNOON MIXING DEPTH TO
BETWEEN 850-825 MB…WHICH SHOULD ALLOW FOR MAX TEMPS TO REACH THE
LOWER/MID 50S IN MOST VALLEYS…EXCEPT FOR SOME UPPER 50S ACROSS
THE MID HUDSON VALLEY. ACROSS HIGHER ELEVATIONS…MAX TEMPS SHOULD
GENERALLY ONLY REACH THE 40S…WITH SOME 30S ACROSS THE HIGHEST
PEAKS OF THE ADIRONDACKS. WITH LOW LEVEL WINDS VEERING INTO THE
W/NW…CHANNELED FLOW DOWN THE MOHAWK RIVER VALLEY SHOULD ALLOW
FOR RATHER GUSTY WINDS IN THIS REGION…AND ALSO EXTENDING FROM
THE CAPITAL REGION INTO THE BERKSHIRES…WHERE SOME GUSTS UP TO 35
MPH WILL BE POSSIBLE.

WED NT…CLOUDS AND ANY LINGERING SHOWERS SHOULD DIMINISH FROM W
TO E IN THE EVENING. THIS MAY ALLOW FOR A PERIOD OF MOSTLY CLEAR
SKIES AND LIGHT WINDS…BEFORE HIGH AND MID LEVEL CLOUDS INCREASE
FROM THE W TOWARD DAYBREAK THURSDAY. DEPENDING ON HOW LONG THESE
CONDITIONS LAST…MAY ALLOW FOR FROST AND/OR FREEZE CONDITIONS TO
OCCUR IN PORTIONS OF THE EASTERN MOHAWK VALLEY…THE HUDSON RIVER
VALLEY…AND ACROSS WESTERN NEW ENGLAND WHERE THE GROWING SEASON
IS UNDERWAY. WE CURRENTLY HAVE FORECAST MINS IN THE LOWER TO MID
30S ACROSS MANY OF THESE AREAS…WITH 20S POSSIBLE ACROSS THE
SOUTHERN ADIRONDACKS.

THU/THU NT…CLIPPER LIKE SYSTEM WILL APPROACH FROM THE GREAT
LAKES REGION DURING THU. MODELS SEEM TO DEPICT TWO POTENTIAL
SOURCES OF LIFT AND SFC PRESSURE FALLS…ONE PASSING ACROSS THE
SOUTHERN ADIRONDACKS…AND ANOTHER POSSIBLY REDEVELOPING OFF THE
NJ COAST. SHOULD ENOUGH LIFT AND/OR EMBEDDED CONVECTION DEVELOP
WITH THE SOUTHERN FEATURE…THIS MAY ROB SOME MOISTURE TRANSPORT
NORTHWARD INTO OUR REGION…RESULTING IN LESS QPF…WITH PERHAPS
ONLY A ROUND OR TWO OF SHOWERS IN THE AFTERNOON/EVENING.
HOWEVER…SHOULD THIS SOUTHERN FEATURE BE LESS
PROMINENT…MOISTURE TRANSPORT INTO OUR REGION MAY BE
STRONGER…AND COULD ALLOW FOR GREATER AREAL COVERAGE OF
SHOWERS…AND EVEN EMBEDDED TSTMS ACROSS THE REGION. WILL INDICATE
LIKELY POPS FOR THE AFTERNOON HOURS…AND ONLY CHC FOR THE
MORNING. IN FACT…THERE IS A CHANCE THAT SOME BREAKS IN THE
CLOUDS OCCUR IN THE MORNING HOURS FROM THE HUDSON RIVER VALLEY
INTO WESTERN NEW ENGLAND. SHOWERS SHOULD TAPER OFF FROM W TO E THU
EVE…ALTHOUGH SOME UPSLOPE SHOWERS OF RAIN/SNOW MAY LINGER ACROSS
THE WESTERN ADIRONDACKS LATE THU NT. FOR TEMPS…GENERALLY TOOK
BLEND OF MAV/MET MOS FOR THU MAXES…WITH 55-60 IN VALLEYS…AND
40S TO LOWER 50S ACROSS NORTHERN AREAS…AND HIGHER TERRAIN. FOR
THU NT…GENERALLY SIDED CLOSER TO THE MET MOS…WITH 35-40 IN
VALLEY REGIONS…AND 20S TO LOWER 30S ACROSS HIGHER ELEVATIONS.
GUSTY W/NW WINDS WILL BE POSSIBLE IN THE WAKE OF THE COLD/OCCLUDED
FRONT THU NIGHT.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/…
MOS GUIDANCE. AS LOW PRESSURE BECOMES CUT OFF OVER THE CANADIAN
MARITIMES…A SECONDARY COLD FRONT WILL BRING SHOWERS TO THE AREA
NORTH AND WEST OF THE CAPITAL REGION ON FRIDAY. HIGH PRESSURE WILL
RIDGE IN FROM SOUTH CENTRAL CANADA TO BRING A DRY START TO THE
WEEKEND. LOW PRESSURE OVER THE MIDDLE OF THE COUNTRY WILL TRACK
EAST TOWARD THE MID-SOUTH/MID-ATLANTIC…BRINGING ANOTHER CHANCE OF
RAIN TO OUR FORECAST AREA…MAINLY FOR SUNDAY.

THE SAME HIGH SETTLES IN FOR MONDAY…ALTHOUGH A NORTHWEST FLOW
COULD PRODUCE SOME LAKE EFFECT SNOW FOR THE WESTERN ADIRONDACKS
MONDAY NIGHT. AS THE HIGH BECOMES CENTERED OVER THE MID-ATLANTIC…
WINDS WILL SLACKEN AND DRY CONDITIONS WILL RETURN FOR TUESDAY.

HIGH TEMPERATURES WILL RANGE FROM THE MID 40S TO LOWER 60S ON
FRIDAY…MAINLY THE LOWER 40S TO MID 50S ON SATURDAY AND SUNDAY…
WITH MOSTLY THE 50S ON MONDAY…AND LOWER 40S TO LOWER 60S ON
TUESDAY. LOWS WILL BE IN MAINLY THE 20S AND 30S…WITH COLDER
SPOTS IN THE HIGH PEAKS OF THE ADIRONDACKS AND GREENS POSSIBLE
FRIDAY AND SATURDAY NIGHTS. ALBANY/S NORMAL HIGHS AND LOWS FOR THE
PERIOD ARE GENERALLY MID 60S AND LOWER 40S.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/…
AN UPPER LEVEL LOW WILL CONTINUE TO AFFECT THE AREA THROUGH TOMORROW
MORNING. VFR CEILINGS SHOULD PREVAIL OUTSIDE OF SCATTERED SHOWERS.
ACKNOWLEDGING VCSH AT ALL SITES THROUGH ABOUT 00Z WHEN THE
ATMOSPHERE SHOULD STABILIZE AND COVERAGE OF SHOWERS SHOULD
DECREASE. ANY SHOWERS SHOULD BE SO BRIEF THAT NO TEMPO IS
NEEDED…SO JUST KEEPING VCSH AND WILL AMEND IF RADAR TRENDS SUPPORT
MVFR/IFR CONDITIONS IN A BRIEF SHOWER. VFR CEILINGS SHOULD CONTINUE
THROUGH TONIGHT AND TOMORROW MORNING AND LEAVING OUT THE VCSH AFTER
00Z UNTIL NEAR TERM RADAR AND SATELLITE DATA CAN BE CHECKED THIS
EVENING.

WINDS WILL BE SOUTH TO SOUTHWEST AT 10 TO 15 KT WITH SOME GUSTS OVER
25 KT THE REST OF THIS AFTERNOON. WINDS WILL DIMINISH TO LESS THAN
10 KT TONIGHT. WINDS INCREASE TO AROUND 10 KT TOMORROW MORNING. SOME
GUSTINESS TO NEAR 20 KT SHOULD OCCUR TOMORROW MORNING AS WINDS TREND
TO MORE WEST BY LATE MORNING.

.OUTLOOK…
WED NGT…VFR. NO SIG WX.
THU…VFR/MVFR. -SHRA LIKELY.
THU NGT…VFR/MVFR…SCT -SHRA EARLY.
FRI…VFR. WINDY.
SAT…VFR. NO SIG WX.
SUN…VFR/MVFR ISOLD/SCT -SHRA.

&&

.FIRE WEATHER…
A STRONG LOW PRESSURE SYSTEM WILL CONTINUE MOVING NORTHWARD INTO
EASTERN CANADA TONIGHT INTO WEDNESDAY. WEAK DISTURBANCES ROTATING
AROUND THIS LOW WILL KEEP COOL TEMPERATURES AND LOTS OF CLOUDS
AROUND THE REGION INTO WEDNESDAY…ALONG WITH THE POSSIBILITY OF
SOME SHOWERS OF RAIN AND WET SNOW…PARTICULARLY ACROSS HIGHER
TERRAIN. ANOTHER LOW PRESSURE SYSTEM APPROACHING FROM THE WEST
WILL BRING SHOWERS TO THE REGION THURSDAY AFTERNOON AND EVENING.

THE RH WILL RECOVER INTO THE 80-90 PERCENT RANGE TONIGHT…THEN
FALL INTO THE 35-45 PERCENT RANGE IN VALLEYS…AND 45-60 PERCENT
RANGE ACROSS HIGHER ELEVATIONS WED AFTERNOON. FOR WED NT…THE RH
SHOULD RECOVER TO 90-100 PERCENT…WITH AREAS OF FROST AND OR DEW
POSSIBLE.

WINDS WILL REMAIN FROM THE SOUTH TO SOUTHWEST AT 5-15 MPH
TONIGHT…THEN VEER INTO THE WEST TO NORTHWEST BY WED
AFTERNOON…AND INCREASE TO 15-25 MPH…WITH SOME GUSTS UP TO 35
MPH POSSIBLE. W/NW WINDS WILL BECOME LIGHT AND VARIABLE LATE WED
NIGHT.

&&

.HYDROLOGY…
ONLY LIGHT PRECIPITATION IS EXPECTED OVER THE NEXT 24 HOURS…WITH
GENERALLY LESS THAN ONE QUARTER OF AN INCH OF QPF EXPECTED ACROSS
NORTHERN AREAS…SOME OF WHICH MAY BE IN THE FORM OF SNOW.

ADDITIONAL SHOWERS MAY PRODUCE BETWEEN ONE QUARTER…AND ONE HALF
OF AN INCH OF QPF THURSDAY INTO THURSDAY EVENING…WITH THE
GREATEST AMTS POSSIBLE ACROSS NORTHERN AREAS. THIS RAINFALL SHOULD
HAVE NEGLIGIBLE IMPACT ON AREA RIVERS AND STREAMS.

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…KL/GJM
NEAR TERM…KL
SHORT TERM…KL
LONG TERM…ELH
AVIATION…NAS
FIRE WEATHER…KL
HYDROLOGY…KL

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