438
FXUS61 KALY 210526
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
1219 AM EST SAT NOV 21 2009
SYNOPSIS
AN UPPER LEVEL WEATHER DISTURBANCE WILL MOVE UP THE SAINT LAWRENCE
VALLEY OVERNIGHT FROM NEAR MONTREAL TO LABRADOR. HIGH PRESSURE WILL
BUILD INTO NEW YORK AND NEW ENGLAND THROUGH MONDAY FROM THE
MIDWEST AND GREAT LAKES REGION. HIGH PRESSURE WILL REMAIN OVER
THE NORTHEAST THROUGH EARLY NEXT WEEK.
NEAR TERM /UNTIL 6 AM THIS MORNING/
UPDATED DEW POINT...POPS AND SKY COVER GRIDS. INCREASED CLOUDS
SLIGHTLY THROUGH TOMORROW MORNING TO REPRESENT OVC SKIES ESP OVER
ADIRONDACKS AND NORTH COUNTRY. EVEN THOUGH SKY GRIDS
INCREASED...TEMPS AND MIN TEMP STILL ON TARGET. DECREASED POPS AS
RADAR SHOWS DECREASING DBZS ACROSS HERKIMER AND HAMILTON
COUNTIES...AND UPPER LOW CONTINUES TO MOVE NORTHEAST OUT OF THE
AREA..WITH WINDS SHOWING A SLIGHT AND GRADUAL DECREASE.
OTHERWISE...CURRENT FORECAST IN GOOD SHAPE.
PREVIOUS DISCUSSION FOLLOWS...
AN UPPER LEVEL LOW PASSING TO OUR NORTH THIS AFTERNOON. WILL BE UNDER
CYCLONIC FLOW TONIGHT ALONG WITH LAKE ENHANCEMENT. HAVE KEPT CHANCE
POPS NORTH AND WEST OF CAPITAL DISTRICT WITH SLIGHT CHANCE POPS
INTO THE CAPITAL DISTRICT FOR THIS EVENING. GUIDANCE IS IN FAIRLY
GOOD AGREEMENT WITH TEMPERATURES FOR TONIGHT...IN THE 30S. LOOKING
AT RAIN SHOWERS WITH SOME SNOW SHOWERS POSSIBLE ACROSS THE HIGHER
TERRAIN OF THE WESTERN ADIRONDACKS. WESTERLY FLOW WEAKENS TONIGHT.
SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/
FOR THE WEEKEND WE HAVE GOOD MODEL AGREEMENT. A SERIES OF 500 HPA
SHORT WAVES PRODUCE A TROFF FM YUL TO ORD ACROSS THE GRTLKS
RGN...WHILE HIGH PRESSURE BUILDS AT THE SFC OVER THE MIDWEST AND
GRTLKS. MODELS SHOW AN AREA OF HI RH MAINLY WELL WEST OF FCA...BUT
ENOUGH TO RESULT IN PS CONDS SAT. THIS AREA DYNAMICS DRYS OVER
TIME AS THE CENTER OF THE SFC HIGH BUILDS OVER FCA...AND WEAK
500HPA TROF AXIS SLIDES SE OF RGN SAT NIGHT. SUNDAY WOULD BRING
M.S. CONDS AS 500 HPA RIDGE BUILDS OVR THE GRTLKS AND SFC HIGH IS
OVER RGN. WITH LT WINDS AND A GOOD BIT OF SUNSHINE...PARTICULARLY
SUNDAY...WEEKEND SHOULD BRING NR TO SLIGHTLY ABV NORMALS TEMPS
WITH MID 40S TO MID 50S.
SUNDAY NIGHT AND MONDAY THE MDLS DIVERGE SIGNIFICANTLY IN THE
DEVELOPMENT...TIMING AND TRACK OF A COASTAL LOW. HPC...NAM...AND
THE GFS ENSEMBLE MEANS KEEP THE SYSTEM WELL SUPPRESSED TO OUT
SOUTH RESULTING IN MOSTLY CLEAR NIGHT SUNDAY NIGHT...AND PS-MS
CONDS MUCH OF MONDAY. BGM PLANS ON SLOWING THE PCPN THREAT
CONSIDERABLY IN THIS PERIOD AND BTV WILL KEEP IT DRY AND FAIR AS
WE WILL WITH ONLY A SLIGHT CHC ACROSS THE SOUTHERN TIER. WITH CLEAR
SKIES STARTED WITH COLD MET TEMPS AND TOOK THEM A FEW DEGREES
LOWED SUNDAY NIGHT. WITH MORE SUN ON MON
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
OPERATIONAL GFS OUTLIER IN GUIDANCE WITH COASTAL LOW MONDAY
THROUGH TUESDAY. ECMWF KEEPS FA DRY THROUGH THURSDAY AS HIGH
PRESSURE STAYS IN PLACE. THURSDAY INTO FRIDAY...TROUGH APPROACHES
FROM THE WEST...WITH A POSITIVE TILT BY LATE FRIDAY. PRECIP
MOVING OUT OF THE FA LATE FRIDAY INTO SATURDAY.
MONDAY NIGHT INTO TUESDAY MORNING LOW TEMPS EXPECTED IN THE M/U30S
IN THE VALLEYS AND L30S IN THE HIGHER TERRAIN. WARMING TO THE
M50S IN THE VALLEYS AND M/U40S IN THE HIGHER TERRAIN DURING THE
DAY. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT A DEGREE OR TWO WARMER
BEFORE THE PRECIP SLOWLY MOVES ITS WAY IN ON THURSDAY. THURSDAY
MAX TEMPS IN THE M40S IN THE VALLEYS AND U30S IN THE HIGHER
TERRAIN...WITH ANY PRECIP DURING THE DAY AS RAIN...WITH SPOTS OF
-RASN ABV 2500FT. COOLER TEMPERATURES THURSDAY NIGHT WILL LEAD TO
RAIN MIXING WITH SNOW AND ALL SNOW AT TIMES. THURSDAY NIGHT
EXPECTING RAIN/SNOW MIX IN THE VALLEYS AND SNOW AT ELEVATIONS
500FT AND ABV. WITH CONDITIONS DRYING LATE FRIDAY...TEMPERATURES
A BIT COOLER ON FRIDAY WITH MAX TEMPS IN THE L/M40S IN THE
VALLEYS AND M/U30S IN THE HIGHER TERRAIN.
AVIATION /05Z SATURDAY THROUGH WEDNESDAY/
HIGH PRESSURE WILL BUILD EAST ACROSS THE REGION SATURDAY THROUGH
SUNDAY.
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES THROUGH AT LEAST
SATURDAY EVENING...ALTHOUGH A BRIEF PERIOD OF MVFR CIGS IS
POSSIBLE AT KGFL THROUGH ABOUT 14Z/SAT. HOWEVER...DUE TO LOW
PROBABILITY...HAVE NOT INDICATED THIS IN 06Z/SAT TAF ISSUANCE.
SOME PATCHY GROUND FOG COULD DEVELOP PRIOR TO 06Z/SUN AT KGFL DUE TO
GROUND FOG FORMATION...WITH A BETTER CHANCE EXPECTED THEREAFTER.
WINDS WILL REMAIN FROM THE W TO NW AT 5-10 KT TODAY...BECOMING
LIGHT/VARIABLE TONIGHT. SOME GUSTINESS IS POSSIBLE THROUGH SAT
MORNING...ESP AT KALB...POSSIBLY REACHING 15-20 KT. IN ADDITION...AT
KGFL...SOME VARIATIONS IN WIND DIRECTION IS POSSIBLE THIS AFTERNOON
DUE TO LOCALIZED TOPOGRAPHICAL EFFECTS.
OUTLOOK...
SUN...VFR...NO SIG WX.
MON-TUE...VFR-MVFR...CHC OF RAIN.
WED...VFR...CHC OF SHOWERS.
HYDROLOGY
WATER LEVELS EXPECTED TO CONTINUE TO RISE ANOTHER HALF OF A FOOT
OR LESS IN REACTION TO LAST NIGHT/S RAINFALL. AS HIGH PRESSURE
BUILDS IN...EXPECT DRY CONDITIONS THROUGH AT LEAST MONDAY. WATER
LEVELS WILL THEN REMAIN NEARLY STEADY OR RECEDE. OUR NEXT CHANCES
FOR WIDESPREAD RAINFALL WILL BE THURSDAY INTO FRIDAY.
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...KGS/SNYDER
NEAR TERM...IAA/KGS
SHORT TERM...SNYDER
LONG TERM...KGS
AVIATION...KL/KGS/IAA
HYDROLOGY...KGS
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