774 
FXUS61 KALY 311141
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
741 AM EDT SAT AUG 31 2013

.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL IMPACT EASTERN NEW YORK 
AND WESTERN NEW ENGLAND THROUGH THE HOLIDAY WEEKEND.  A SERIES OF 
WEAK DISTURBANCES MOVING ALONG A FRONTAL BOUNDARY NEAR THE SAINT 
LAWRENCE RIVER VALLEY WILL PRODUCE SHOWERS AND THUNDERSTORMS TODAY 
WITH SOME LOCALLY HEAVY RAINFALL.  THE UNSETTLED WEATHER CONTINUES 
LATE SUNDAY INTO LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE 
WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS TO THE REGION.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 655 AM EDT...THE LAST FULL DAY OF AUGUST AND METEOROLOGICAL
SUMMER BEGAN WITH SHOWERS AND SCT THUNDERSTORMS ACROSS PORTIONS OF
THE ALY FCST AREA...ESPECIALLY FROM THE NRN CATSKILLS...CAPITAL
REGION AND SRN VT NORTHWARD. A COUPLE OF WEAK SFC LOWS ARE MOVING
ALONG A STATIONARY FRONT NEAR THE ST LAWRENCE RIVER VALLEY AND ERN
GREAT LAKES THIS MORNING. LOW-LEVEL CONVERGENCE WITH THE SFC LOWS
HAS HELPED THE SHOWERS AND THUNDERSTORMS BE THE MOST PERSISTENT IN
THE MOHAWK RIVER VALLEY...SRN DACKS...AND THE LAKE GEORGE SARATOGA
REGION. THIS ACTIVITY WILL CONTINUE TO WANE EARLY THIS MORNING...AND
A BRIEF LOW WILL OCCUR TOWARDS NOONTIME. THE POPS WERE RETRENDED
THIS MORNING BASED ON THE RADAR TRENDS. 

A MAJORITY OF THE GUIDANCE SHOWS ANOTHER WEAK RIPPLE OF LOW
PRESSURE MOVING ALONG THE BOUNDARY IN THE AFTERNOON WITH A MID
LEVEL SHORT-WAVE IN THE W/SW FLOW ALOFT. IT IS QUESTIONABLE IF ANY
SIGNIFICANT HEATING WILL OCCUR EXCEPT PERHAPS ALONG THE SRN TIER
OF THE FCST AREA /MID HUDSON VALLEY AND NW CT/. THE 0-6 KM DEEP
SHEAR IS WEAK WITH WEAK MID LEVEL LAPSE RATES ALOFT...SO
WIDESPREAD SEVERE CONVECTION IS NOT ANTICIPATED DESPITE SBCAPE
VALUES OF 1000-2000 J/KG ACCORDING THE NAM/GFS. H850 THETA-E
VALUES WILL BE GENERALLY IN THE 335-340K RANGE. THE PWATS WILL BE
IN THE 1.25-1.75 INCH RANGE /1 TO 2 STANDARD DEVIATIONS ABOVE
NORMAL/...SO LOCALLY HVY RAINFALL WILL BE THE MAIN ISSUE. THE
ENHANCED WORDING WAS PUT IN THE GRIDS...AND WILL BE MENTIONED IN
THE HWO. IF THE HIGHER CAPE VALUES ARE REALIZED...AN ISOLATED WET
MICROBURST MAY BE POSSIBLE. THE MAIN THREAT CONTINUES TO BE HEAVY
RAINFALL. THE HIGHEST POPS IN THE LIKELY RANGE WERE USED ACROSS
THE NRN HALF OF THE FCST AREA. 

THE 07Z 3KM HRRR COLUMN REF PRODUCT SHOWS DISCRETE CONVECTIVE
ELEMENTS FORMING INTO A LINE OVER THE HUDSON RIVER VALLEY IN THE
MID AFTERNOON. IN A WEAK SHEAR ENVIRONMENT THIS APPEARS TO BE OFF
SOME...BUT WILL HAVE TO BE MONITORED. LATER RUNS HAVE SHOWN LESS
SIGNIFICANT COVERAGE AND ORGANIZATION. 

THE SFC DEWPTS WILL REMAIN IN THE 60S WITH PERHAPS SOME SPOTTY
LOWER 70S OVER THE SRN TIER. THE AIR MASS WILL BE STICKY FOR THE
LAST DAY OF AUGUST. MINIMAL HEATING SHOULD ALLOW FOR U70S TO L80S
IN THE VALLEYS...WITH 70S OVER THE HILLS AND MTNS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...THE SHOWERS AND THUNDERSTORMS SHOULD DIMINISH IN THE
EARLY EVENING WITH THE WEAK SFC WAVE MOVING EAST/NORTHEAST OF THE
REGION...AND THE MID LEVEL SHORT-WAVE PASSING DOWNSTREAM. THE
FRONTAL BOUNDARY MAY MOVE OVER THE NRN HALF OF THE FCST AREA AND
FALL APART. THE POPS WERE LOWERED TO SLIGHT CHC VALUES AFTER
MIDNIGHT. IT WILL REMAIN VERY HUMID WITH LOWS IN THE MID AND U60S
OVER MOST OF THE REGION...EXCEPT OVER THE MTNS.

SUNDAY...THE ENTIRE DAY SHOULD NOT BE A WASHOUT WITH AN AMPLIFYING
UPPER LEVEL TROUGH OVER ONTARIO AND THE GREAT LAKES REGION. THE
MID LEVEL FLOW WILL BECOME SOUTHWESTERLY OVER NY AND NEW ENGLAND
WITH WEAK RIDGING ALOFT. THEIR ARE NOT ANY REAL ROBUST SYNOPTIC
TRIGGER MECHANISMS DURING THE DAY. AIR MASS OR DIFFERENTIAL
HEATING THUNDERSTORMS ARE POSSIBLE. A SLIGHT TO LOW CHANCE OF
SHOWERS AND THUNDERSTORMS WAS INCLUDED IN THE GRIDS. H850 TEMPS
INCREASE TO +16C TO +17C WITH PARTLY SUNNY CONDITIONS. MAX TEMPS
WILL RUN ABOUT 5-10 DEGREES ABOVE NORMAL TO OPEN SEPT.

SUNDAY NIGHT INTO LABOR DAY...A LARGE TROUGH OF LOW PRESSURE
IMPACTS THE REGION. SEVERAL MID LEVEL SHORT-WAVES ROTATING AROUND
THE CLOSED LOW SOUTH OF JAMES BAY WILL YIELD UNSETTLED WX DURING
THIS TIME FRAME. IT IS DIFFICULT TO DETERMINE IF ANY ROBUST SFC
HEATING WILL OCCUR AT THIS TIME. THE STRONG SYNOPTIC LIFT WITH THE
TROUGH WILL LIKELY YIELD PERIODS OF SHOWERS AND SCT THUNDERSTORMS.
SOME HVY RAINFALL LOOKS LIKE A GOOD BET. THE QG LIFT INCREASES
LABOR DAY AFTERNOON...AS THE NRN HALF OF THE FCST AREA GETS NEAR
THE RIGHT ENTRANCE REGION OF A H250 JET STREAK WITH STRONG UPPER
LEVEL DIVERGENCE ALOFT. PWATS CONTINUE ABOVE NORMAL FOR EARLY
SEPT. LIKELY POPS WERE CONTINUED ON MONDAY. THE COOLER NAM MOS
TEMPS WERE ALSO FOLLOWED CLOSELY WITH THE AMOUNT OF CLOUD COVER
AND NUMEROUS SHOWERS EXPECTED. MAX TEMPS WILL BE HARD PRESSED TO
GET OUT OF THE 70S WITH PERHAPS SOME 80F READINGS FROM THE CAPITAL
REGION SOUTH IN THE MID HUDSON VALLEY.

MONDAY NIGHT...LOW AND MID LEVEL HEIGHTS CONTINUE TO FALL...AS THE
TROUGH OF LOW PRESSURE AND ITS ASSOCIATED COLD FRONT MIGRATE EAST
OF THE REGION. A CHC OF SHOWERS WAS KEPT IN MOST OF THE OVERNIGHT.
LOW LEVEL COLD ADVECTION IS EXPECTED WITH TEMPS FALLING INTO THE
50S OVER THE MTNS WITH LOWER TO MID 60S IN THE VALLEYS.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
COOLER AND LESS ACTIVITY WEATHER AS WE HEAD THROUGH THE FIRST WEEK 
OF SEPTEMBER. 
 
THE MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT REGARDING THE 
LONGWAVE PATTERN WITH THE NORTHEAST REMAINING UNDER A TROUGH AND
THE RIDGE HOLDING ON OVER THE PLAIN STATES. 

A COUPLE OF COLD FRONTS WILL MOVE ACROSS THE REGION. THE FIRST ONE 
IS EXPECTED TO MOVE OFF TO OUR EAST ON TUESDAY WITH SOME LINGERING 
SHOWERS POSSIBLE MAINLY DURING THE MORNING. A PLEASANT DAY EXPECTED 
WEDNESDAY AS HIGHER PRESSURE BUILDS IN WITH SEASONABLE WARM 
TEMPERATURES. A SECONDARY COLD FRONT IS EXPECTED TO MOVE THROUGH 
THURSDAY WITH ISOLATED SHOWERS. A MORE AUTUMN-LIKE AIRMASS WILL BE 
USHERED IN AS CANADIAN HIGH PRESSURE BUILDS IN ITS WAKE OF THE FRONT 
TO CLOSE OUT THE WEEK. TEMPERATURES THURSDAY AND FRIDAY ARE 
ANTICIPATED TO RUN ABOUT 5 DEGREES BELOW NORMAL.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SOME SHOWERS CONTINUE TO MOVE EASTERLY ACROSS THE FORECAST AREA 
EARLY THIS MORNING IN ASSOCIATION WITH A PASSING SHORT WAVE TROUGH 
AND WEAK SURFACE LOW MOVING INTO THE SAINT LAWRENCE RIVER VALLEY. 
EXPECT A LULL IS THE PRECIPITATION FOR A BIT THIS MORNING AS THE 
SHORT WAVE TROUGH MOVES OFF TO THE EAST. HOWEVER...CHANCES FOR 
CONVECTION WILL INCREASE AS HEAD INTO THE AFTERNOON AS THE SURFACE 
LOW PASSES TO OUR NORTH AND ANOTHER SHORT WAVE TROUGH APPROACHES. 
WITH THE HELP OF DIURNAL HEATING AND INCREASED INSTABILITY THERE WILL 
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS. DO NOT HAVE CONFIDENCE 
TO TIME THUNDERSTORMS AT INDIVIDUAL TAF SITES SO HAVE RUN WITH A 
TEMPO GROUP FOR SHOWERS TO HIGHLIGHT MOST LIKELY TIME FOR CONVECTION 
TO OCCUR.

ALTHOUGH LOW VSBYS/CIGS ARE ALLOWING FOR OCCASIONAL IFR AND MVFR
CONDITIONS EARLY THIS MORNING...AN IMPROVEMENT TO VFR CONDITIONS
IS EXPECTED BY LATE THIS MORNING. MVFR WITH BRIEF IFR CONDITIONS
ARE EXPECTED WITH ANY CONVECTION THAT IMPACTS TAF SITES TODAY.
MVFR/IFR FOG/CIGS ARE EXPECTED TO DEVELOP TONIGHT...ESPECIALLY WHERE
IT RAINS.

OUTLOOK...
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. 
LABOR DAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. 
TUESDAY: LOW OPERATIONAL IMPACT. CHANCE OF SHRA.
TUESDAY NIGHT-WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE EXPECTED IN THE HUMID AIR MASS WITH
SEVERAL CHANCES OF RAINFALL.

A SERIES OF WEAK DISTURBANCES MOVING ALONG A FRONTAL BOUNDARY
NEAR THE SAINT LAWRENCE RIVER VALLEY WILL PRODUCE SHOWERS AND
THUNDERSTORMS TODAY WITH SOME LOCALLY HEAVY RAINFALL. THE
UNSETTLED WEATHER CONTINUES LATE SUNDAY INTO LABOR DAY WHEN A
STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS TO THE REGION.

THE RH VALUES WILL ONLY DROP TO BETWEEN 50 AND 85 PERCENT THIS 
AFTERNOON...AND RECOVER TO CLOSE TO 100 PERCENT SUNDAY MORNING.
HIGH RH VALUES OF 55 TO 75 PERCENT WILL OCCUR SUNDAY AFTERNOON.

THE WINDS WILL BE FROM THE SOUTH TO SOUTHWEST AT 5 TO 15 MPH TODAY
AND TOMORROW... AND BECOME LIGHT TO CALM TONIGHT.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS.
THE BEST CHANCE FOR WIDESPREAD RAINFALL WILL BE TODAY AND ON
LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. ISOLATED URBAN...SMALL STREAM...AND
POOR DRAINAGE FLOODING WILL BE POSSIBLE DURING THE HOLIDAY
WEEKEND. SOME WITHIN BANK RISES ARE POSSIBLE ON LARGER STREAMS
WHERE SHOWERS AND STORMS OCCUR. ZONAL FFG VALUES REMAIN HIGH
DURING THIS TIME FRAME. HOWEVER...A QUICK INCH OR TWO OF RAINFALL
FROM A SLOW MOVING THUNDERSTORM MAY PRODUCE AN ISOLATED FLASH
FLOOD DURING THE HOLIDAY WEEKEND.

RAINFALL AMOUNTS WILL BE QUITE VARIABLE DUE TO THE SHOWERY NATURE
OF THE RAIN...WITH SOME LOCATIONS RECEIVING OVER AN INCH OF RAIN
WHILE OTHERS REMAIN DRY. SOME AREAS NORTH OF THE CAPITAL REGION
HAVE RECEIVED A HALF AN INCH TO AN INCH OF RAINFALL THIS MORNING.

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...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA/FRUGIS
FIRE WEATHER...WASULA
HYDROLOGY...SND/WASULA