624
FXUS61 KALY 072038
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
338 PM EST SAT NOV 7 2009
SYNOPSIS
HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT. A SOUTHERLY FLOW WILL
EVENTUALLY BRING MILDER AIR OUR WAY BY SUNDAY. HIGH PRESSURE
OFFSHORE WILL REMAIN IN CONTROL OF OUR WEATHER THROUGH MONDAY.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
UPPER SYSTEM TRACKING JUST NORTH OF THE GREAT LAKES WILL LIFT
THROUGH EASTERN CANADA AS UPPER AND LOW LEVEL RIDGING REINFORCES
ACROSS EASTERN NORTH AMERICA. BOUNDARY LAYER TEMPERATURES WILL
CONTINUE TO WARM...AND A LIGHT SOUTH WIND...ESPECIALLY IN HIGHER
ELEVATIONS...AND ANY VALLEYS THAT CHANNEL WINDS. THIS MAKES FOR
SOME STRANGE ISSUES AS FAR AS POTENTIAL LOCAL EFFECTS AND LOW
TEMPERATURES TONIGHT. THERE COULD BE SOME NOTICEABLE DIFFERENCES
IN LOW TEMPERATURES IN SHORT DISTANCES ACROSS THE REGION...BUT
EVEN MORE SO TOMORROW NIGHT...BUT THAT WILL BE ADDRESSED IN THE
NEXT SECTION.
THERE ARE SOME INDICATIONS THAT A SHALLOW MOISTURE LAYER WILL
CONTRIBUTE TO A BROKEN CLOUD DECK LATER TONIGHT AND AROUND
SUNRISE...WHICH WOULD LIMIT THE TEMPERATURE FALLS IN SOME AREAS
OVERNIGHT. LOWS TONIGHT IN THE 30S...AROUND 40 IN WARMER
SPOTS...AROUND 30 IN COLDER SPOTS.
SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/
WARM ADVECTION WILL CONTINUE SUNDAY AND MONDAY...WITH BOUNDARY
LAYER TEMPERATURES CONTINUING TO WARM. SOUTHWEST BOUNDARY LAYER
FLOW WILL CONTINUE TO INCREASE...ESPECIALLY MONDAY. THE RELATIVE
LACK OF DEEP MOISTURE WILL RESULT IN LIMITED CLOUD COVER...SO EVEN
WITH THE RAPIDLY LOWERING SUN ANGLE...SOME MIXING SHOULD HELP
TEMPERATURES CLIMB TO AROUND 60 TO LOWER 60S TOMORROW...AND LOWER
TO UPPER 60S MONDAY.
AS FAR AS LOW TEMPERATURES...SUNDAY NIGHT LOWS WILL DEPEND AGAIN
ON WHAT LOCATIONS EXPERIENCE A LIGHT SOUTH WIND...AND WHAT
LOCATIONS GO CALM. THERE COULD BE 10+ DEGREE DIFFERENCES BETWEEN
LOCATIONS THAT SEE CALM WINDS AND THOSE THAT SEE SOUTH WINDS AT
2-5 MPH...SO AROUND FREEZING IN AREAS THAT GO CALM...AND LOW TO
MID 40S IN AREAS THAT SEE LIGHT SOUTH WINDS MOST OF THE NIGHT.
THERE COULD BE SOME THICKENING MID AND HIGH CLOUDS AFTER MIDNIGHT
THAT MAY PREVENT TEMPERATURES FROM FALL AS MUCH AS THEY COULD.
MONDAY NIGHT...INCREASING CLOUD COVER AND STEADY LIGHT SOUTH TO
SOUTHWEST WINDS SHOULD KEEP MOST AREAS IN THE 40S FOR LOWS.
QUITE A BIT OF SPREAD IN GUIDANCE AS TO THE TIMING AND PLACEMENT
OF A SYSTEM APPROACHING FROM THE GREAT LAKES...WITH FASTER
GUIDANCE SUGGESTING A FRONTAL PASSAGE LATE MONDAY NIGHT AND EARLY
TUESDAY MORNING. SLOWER GUIDANCE SUGGESTS CONTINUED PREFRONTAL WARM
SECTOR THROUGH MOST OF THE DAY TUESDAY. AT THIS TIME...SUGGESTING
GRADUAL WIND SHIFT AND SLOWER COOLING...BUT STILL...WITH MOSTLY
CLOUDY AND SOME SCATTERED SHOWERS...HIGHS AROUND 60...50S IN
ADIRONDACKS AND GREEN MOUNTAINS.
MODELS NOT RESOLVING UPSTREAM FEATURES SUCH AS PACIFIC JET
ENERGY...AND IDA APPROACHING GULF OF MEXICO...SO ANY ISSUES FROM
TUESDAY AND BEYOND WILL NOT BE RESOLVED UNTIL FEATURES ENTER
DENSER DATA NETWORK. MORE INFO IN LONG RANGE SECTION.
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
MOST OF THE ATTENTION WILL BE ON THE TROPICS WITH IDA WHICH IS
EXPECTED TO BECOME ABSORBED BY A COLD FRONT THAT IS FORECAST TO
SWING THROUGH THE GREAT LAKES AND NEW ENGLAND TUESDAY NIGHT. THE
GFS WAS DISCOUNTED DURING THE LONG TERM SINCE ITS RELATED ENSEMBLE
DATA DOES NOT SUPPORT ITS OPERATIONAL MEMBERS INCLUDING
INTERNATIONAL GLOBAL MODELS SUCH AS THE ECMWF/GGEM/UKMET. THE
REMNANTS OF IDA SHOULD REMAIN FAR REMOVED FROM THE LOCAL AREA AND
WILL FOLLOW A DRIER SOLUTION HEADING INTO THIS LONG TERM PORTION OF
THE FORECAST.
WITH THAT SAID...SURFACE HIGH BUILDS SOUTHEAST FROM THE UPPER PLAINS
INTO THE MID ATLANTIC BY MID WEEK AND A NEAR ZONAL FLOW ALOFT WILL
PROVIDE MODERATING TEMPERATURES IN THE WAKE OF THE COLD FROPA.
TRENDS AND ENSEMBLE DATA SUGGEST SUBTROPICAL UPPER HIGH/RIDGE
DEVELOPS OFF THE SOUTHEAST CONUS BY WEEKS END WHICH WILL AID IN THE
WARM TRANSPORT FOR THE END OF THE WORK WEEK. THE NEXT CHANCE FOR
PRECIPITATION MAY ARRIVE NEXT WEEKEND AS ANOTHER FRONTAL BOUNDARY IS
EXPECTED TO APPROACH.
TEMPERATURES WILL AVERAGE NEAR TO ABOVE NORMAL WITH BELOW NORMAL
PRECIPITATION.
AVIATION /20Z SATURDAY THROUGH THURSDAY/
AC DECK SHOWING SIGNS OF EROSION AS THE SOUTHERN EDGE SKIRTS BY
GFL...BUT EXPECTING CONTINUED MOISTURE INFLUX AT INCREASINGLY LOWER
LEVELS IN ADVANCE OF A COLD FRONT...SO HAVE GONE BKN050-060 BY 04Z
AT ALL AIRPORTS. BUT ALSO THINK MORE LOW-LEVEL MOISTURE WILL
EVENTUALLY BRING IN SOME SC BELOW 3000 FEET. HAVE GONE WITH AN MVFR
CIG AT GFL AND ALB AFT 10Z.
SLGT WAA AND A FEW CLOUD BREAKS COULD FORM SOME LIGHT WAA FOG WHICH
MAY GO MVFR...XCP HAVE STAYED 6SM AT ALB...ALL AFT 04Z. GFL WILL
HAVE TO BE WATCHED FOR POSSIBLY WORSE VSBY CATEGORY GIVEN THE PAPER
MILL AND NEARLY CALM WIND. EXPECTING THE WEAKENING COLD FRONT
THROUGH AROUND 10Z ON SUNDAY...BUT HAVE LEFT OUT ANY MENTION OF
SHOWERS FOR NOW AS DEEP-LAYER MOISTURE IS SEVERELY LACKING. STILL
WOULDN'T SURPRISE ME TO SEE A FEW BRIEF SPRINKLES EVOLVE AT GFL AND
ALB TOWARD DAYBREAK.
2000-FOOT SOUTHWESTERLY WINDS CARRYING IN THE MOISTURE THIS EVENING
ARE INTO WIND SHEAR CRITERIA. THUS...HAVE A SHORT PERIOD OF 35
KNOTS AT ALL THE AIRPORTS FROM 22Z TO 04Z...THEN FLOW ALOFT
GRADUALLY LESSENS IN WEAKENING ENVIRONMENT. SURFACE WINDS SUNDAY
WILL BE NO MORE SIGNIFICANT THAN TODAY.
OUTLOOK...
SUN PM-MON NGT...VFR...NO WX.
TUE-TUE NGT...-SHRA...CHC MVFR CIG/VSBY.
WED...VFR...NO WX.
HYDROLOGY
NO HYDRO PROBLEMS ARE ANTICIPATED THROUGH THE NEXT THREE DAYS. DRY
WEATHER IS EXPECTED THROUGH MONDAY.
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...NAS
NEAR TERM...NAS
SHORT TERM...NAS
LONG TERM...BGM
AVIATION...ELH
HYDROLOGY...BGM/NAS
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