Area Forecast Discussion
Issued by NWS Albany, NY

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000
FXUS61 KALY 121356
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
956 AM EDT SAT JUL 12 2014

.SYNOPSIS...
HIGH PRESSURE ALONG THE ATLANTIC SEABOARD WILL MOVE OUT TO SEA
THIS AFTERNOON. THIS WILL ALLOW FOR THE RETURN FLOW OF MORE HUMID
AIR BACK INTO THE REGION THIS WEEKEND. ALONG WITH THE INCREASE IN
MOISTURE...THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE ON THE
RISE. SEVERE WEATHER IS POSSIBLE SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 900 AM EDT...SCT CU IN MHWK VLY...MID HUDSON...SCT MID AND
HI CLOUDS ELSEWHERE. MID LEVEL LAPSE RATES REMAIN ELEVATED INCRG
TO 6-7 IN MST GUID AND THE 06UTC GFS TO 6-8C. ADVECTING EXPECTED
MOISTURE BLO 850HPA AND EXPECT MAX TEMPS MRNGS SNDG YIELDS A CAPE
OF 1200 J/KG BY AFTN. NAM MDLS SNGD WITH SAME LOW LVL PROFILE ONLY
RESULTS IN 700 CAPE...DUE TO MID LEVEL WARMING. NAM PRODUCES
600-1000 J/KG W/HIRES WRF ARND 700 J/KG. HI RES WRF/HRRR EXPLICITLY
PROD PRODUCES SOME SCT -SHRA/ISOLD TSTM OVER NY AREAS. THE OTHER
3KM WRF WITH DIFFERENT LOCAL PHYSICS RESULT IN MORE COVERAGE AND
STRONGER SCT TSTMS.

OTRW...HIGH PRESSURE HAS SLID OFF ATLC SEABOARD...AND RETURN FLOW
WILL INCR WM ADVECTION AND LLVL MOISTURE...DURING THE AFTN.  SFC
TD REACH LOW 60S...925HPA TD 15C. ADD A PASSING WK SHRT WV
EVIDENT IN WV IMAGERY AND MDLS FCST...AS SUCH WILL TAKE POPS UP
INTO HIGHER SLGHT CHC RANGE FOR TSTMS THIS AFTN AND MAY HAVE TO GO
HIGHER LATER DEPENDING ON EVOLUTION.

UNDER AN INCREASE CANOPY OF CLOUD COVER...AND H850 TEMPS CLIMBING
INTO THE MID TEENS...SURFACE HIGH TEMPS SHOULD YIELD MID 80S FOR
VALLEY LOCATIONS AND UPR 70S FOR THE TERRAIN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
SEVERE WEATHER POTENTIAL INCREASING FOR SUNDAY...
TONIGHT...WARM FRONT WILL BE APPROACHING FROM THE WEST AS AN MCS
OVER THE CENTRAL-NORTHERN PLAINS QUICKLY TRACKS EAST ALONG AND
NORTH OF I80. MEANWHILE THE VORTEX NEAR WESTERN HUDSON BAY IS
FORECAST TO MIGRATE FURTHER SOUTH TOWARD LAKE WINNIPEG. THE
AGEOSTROPHIC RESPONSE WILL BE AN INCREASING LOW LEVEL JET WITH
SPEED CONVERGENCE OVER UPSTATE NY. THIS WILL KEEP THE THREAT FOR
ADDITIONAL CONVECTION ALONG THE THETA-E RIDGE AXIS OVER THE
WESTERN PORTIONS OF THE REGION LATER TONIGHT. WE WILL CONTINUE
WITH THE PREVIOUS EXCELLENT FORECAST WITH INCREASING POPS FROM
WEST TO EAST OVERNIGHT. THIS OVERNIGHT CONVECTION WILL REMAIN
ELEVATED SO SEVERE WEATHER IS NOT EXPECTED AT THIS TIME.

SUNDAY...THAT POTENTIALLY CHANGES ON SUNDAY AS PER CLOSE
COORDINATION WITH SPC...MOST OF EASTERN NY IS NOW IN A SLIGHT RISK
FOR SEVERE THUNDERSTORMS.  WHILE CONSIDERABLE CLOUD COVER IS
EXPECTED...IT WILL NOT TAKE TOO MUCH FOR SUNNY BREAKS TO OCCUR
IN-BETWEEN CONVECTION. SEVERAL PARAMETERS ARE ADDING UP FOR A
POTENTIALLY ACTIVE DAY. A CLOSE PROXIMITY OF A WARM FRONT...HIGH
PWATS CLOSE TO 2 INCHES...MUCAPES CLOSE TO 2K J/KG PER THE
NAM/GFS...LOW LEVEL HODOGRAPHS EXHIBITING LOW LEVEL CURVATURE WITH
HELICITIES AT OR ABOVE 200 M2/S2 AND LOWERING LCL/S...DAMAGING
WIND THREAT AND AN ISOLATED TORNADO THREAT IS IN THE FORECAST. PER
SPC DISCUSSION...HIGHER SEVERE PROBABILITIES MAY BE WARRANTED IN LATER
OUTLOOKS DEPENDING ON TIMING AND GREATER CONFIDENCE IN DEGREE OF
DESTABILIZATION. HIGHS SHOULD AVERAGE INTO THE LOWER 80S FOR
VALLEY LOCATIONS AND 70S ELSEWHERE...SURFACE DEWPOINTS CLIMB TO
BETWEEN 65F-70F.

SUNDAY NIGHT INTO MONDAY...PLENTY OF MODEL DISCREPANCY AS EITHER A
COLD FRONT WILL SLIDE SLOWLY ACROSS THE REGION OR BECOME QUASI-
STATIONARY AS SUGGESTED BY THE GFS. A COMPROMISE OF THE AVAILABLE
GUIDANCE SUGGESTS THIS FRONT WILL BECOME QUASI-STATIONARY SOUTH OF
I90 AND RETURN BACK AS A WARM FRONT ON MONDAY. THIS WILL CONTINUE
THE THREAT FOR SHOWERS AND THUNDERSTORMS MAINLY FOR THE SOUTHERN
PORTIONS OF OUR CWFA. WITH NOCTURNAL ASPECT SUNDAY
NIGHT...EXPECTATIONS ARE FOR THE SEVERE WEATHER POTENTIAL TO
DIMINISH AS WE LOSE THE SURFACE BASED PARCELS. THAT CHANGES ON
MONDAY WITH THE RETURN OF THE WARM FRONT AN ROOTING THE SURFACE
PARCELS AS A POTENTIALLY ANOTHER ACTIVE DAY MAY BE UNFOLDING. PER
SWODY3 OUTLOOK...OUR SOUTHERN REGIONS ARE JUST OUTSIDE OF THE
SLIGHT RISE WITH THE ENTIRE REGION INTO A GENERAL OUTLOOK. AS FOR
TEMPERATURES THROUGH THE PERIOD...GUIDANCE NUMBERS ARE FAIRLY
CLOSE WITH A BLENDED APPROACH UTILIZED.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ACTIVE WEATHER WILL BE CONTINUING AT THE BEGINNING PORTION OF THE
EXTENDED PERIOD.

ON MONDAY NIGHT INTO TUESDAY...A DEEP CUTOFF UPPER LEVEL LOW WILL BE
MOVING FROM THE GREAT LAKES TOWARDS SOUTHERN CANADA...WITH A SFC
COLD FRONT SLOWLY APPROACHING FROM THE WEST. THERE ARE SIGNIFICANT
DIFFERENCES IN THE PLACEMENT OF THE CUTOFF LOW AT 500 HPA WHEN
COMPARING THE LATEST 00Z GFS...GGEM AND ECMWF. THE ECMWF IS THE
SLOWEST OF ALL THREE MODELS...AND LAGS THE CUTOFF BEHIND THE
LONGEST...WHICH WOULD KEEP A THREAT OF SHOWERS/THUNDERSTORMS IN THE
FORECAST THROUGH AT LEAST MID WEEK.

AS A RESULT OF THE DEEP MERIDIONAL FLOW AHEAD OF THE CUTOFF
LOW...THERE WILL BE A STRONG SOUTHERLY COMPONENT AHEAD OF THIS
SYSTEM ACROSS OUR AREA FOR MONDAY NIGHT INTO TUESDAY. THIS WILL
ALLOW PWAT VALUES TO REACH AROUND 2.00 INCHES...WHICH IS CLOSE TO 2
STD ABOVE NORMAL ACCORDING TO CLIMO.  WITH DAYTIME TEMPS IN THE 70S
TO NEAR 80 AND DEWPOINTS REACHING THE UPPER 60S TO LOW 70S...THERE
WILL BE PLENTY OF MOISTURE AVAILABLE FOR PERIODS OF HEAVY SHOWERS
AND THUNDERSTORMS.  WE WILL HAVE TO WATCH THE POTENTIAL FOR LOCALLY
HEAVY RAINFALL...AS LOCAL STUDIES HAVE SHOWN THESE TYPES OF SETUPS
TO BE CONDUCIVE FOR WIDESPREAD FLASH FLOODING ACROSS OUR AREA.

IN ADDITION...THERE WILL BE THE POTENTIAL FOR STRONG TO SEVERE
T-STORMS...AS THE UPPER LEVEL DYNAMICS SHIFT CLOSER TO OUR
AREA...AND PUTS OUR AREA IN THE RIGHT REAR QUAD /RIGHT ENTRANCE
REGION/ OF A CYCLONICALLY CURVED 130 KT JET AT 250 HPA. THE DEGREE
OF SEVERE WX WILL ULTIMATELY DEPEND ON JUST HOW MUCH INSTABILITY IS
AVAILABLE. IT MAY BE LIMITED DUE TO EXTENSIVE CLOUD COVER...AND
FLASH FLOODING MAY WIND UP BEING A BIGGER THREAT THAN SVR STORMS FOR
MON NIGHT/TUESDAY.

DEPENDING ON WHICH MODEL IS CORRECT...THE COLD FRONT WILL CROSS OUR
AREA SOMETIME BETWEEN TUESDAY AND WEDNESDAY MORNING.  ONCE IT
CROSSES OUR AREA...MUCH LESS HUMID AIR WILL WORK INTO OUR REGION
FROM THE WEST. WITH THE UPPER LOW SLOWLY FILLING IN AND WEAKENING TO
OUR NORTH...CYCLONIC FLOW WILL START KEEP THE THREAT OF A SHOWER IN
THE FORECAST THROUGH WED...AND POSSIBLY EVEN FOR THURSDAY FOR FAR
NORTHERN AREAS. IF THE ECMWF IS CORRECT THOUGH...THERE STILL BE SOME
HEAVY SHOWERS FOR EASTERN AREAS FOR TUESDAY NIGHT INTO WED
MORNING...AS THE FRONT WILL BE CROSSING THROUGH AROUND THAT TIME.

OTHERWISE...THE REMAINDER OF THE WEEK LOOKS QUIET WITH A MOSTLY TO
PARTLY SUNNY SKY...AS SFC HIGH PRESSURE BUILDS INTO THE AREA FROM
THE WEST.  THE UPPER LOW LOOKS TO CONTINUE TO WEAKEN AND LIFT ACROSS
QUEBEC...WITH DRIER... COOLER AND LESS HUMID AIR IN OUR AREA DURING
THE LATE WEEK. DAYTIME TEMPS WILL BE IN THE 70S TO LOW 80S...AND
OVERNIGHT LOWS IN THE 50S TO LOW 60S.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE IS SITUATED EAST OF THE AREA JUST OFF EASTERN NEW
ENGLAND. AS THIS HIGH PRESSURE AREA STARTS TO MOVE AWAY...BKN HIGH
CLOUDS OVER CENTRAL NY AND EASTERN ONTARIO WILL START TO SPREAD OVER
THE TERMINALS DURING THE MORNING HOURS. IN ADDITION TO THE BKN HIGH
LEVEL CLOUDS...SOME DIURNAL CU WILL DEVELOP TODAY...BUT AN INVERSION
AROUND 700 HPA WILL PREVENT ANY CU FROM GROWING VERY TALL.  AS A
RESULT...IT LOOKS TO REMAIN RAIN FREE AT THE TERMINALS TODAY WITH
CONTINUED VFR CONDITIONS. SOUTHERLY WINDS WILL BE AROUND 4-8 KTS.

WINDS LOOK TO DECREASE TO 5 KTS OR LESS FOR THIS EVENING WITH
CONTINUED SCT HIGH CLOUDS AROUND. THERE MAY BE SOME OVERNIGHT FOG AT
KGFL ONCE AGAIN...MAINLY LATE AFTER MIDNIGHT. OTHERWISE...VFR
CONDITIONS LOOK TO CONTINUE FOR ALL SITES THROUGH THE OVERNIGHT
HOURS. MID AND HIGH LEVEL CLOUDS WILL INCREASE LATE AT NIGHT AS A
WARM FRONT STARTS TO APPROACH FROM THE WEST.

OUTLOOK...

SUNDAY NIGHT THROUGH TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT.
CHANCE OF SHRA...TSRA.
WEDNESDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
WEDNESDAY NIGHT THROUGH THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.FIRE WEATHER...
AS HIGH PRESSURE SLIDES OFFSHORE...THE RETURN FLOW WILL INCREASE
LOW LEVEL MOISTURE THROUGH THE REMAINDER OF THE WEEKEND. THIS IN
TURN WILL ALSO INCREASE THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS...SOME CONTAINING HEAVY RAINFALL.

MINIMUM RH VALUES THIS AFTERNOON WITH GENERALLY FALL BETWEEN 40
AND 50 PERCENT...AN RECOVER TO VALUES AT OR ABOVE 90 PERCENT.
THOSE VALUES REMAIN ELEVATED ON SUNDAY WITH VALUES AT OR ABOVE 60
PERCENT.

LIGHT WINDS WILL BECOME SOUTHERLY AT 10 MPH OR LESS TODAY INTO
TONIGHT. THE MAGNITUDES INCREASE THROUGH SUNDAY WITH 10 TO 15 MPH.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED INTO TONIGHT...BUT
THEN A SERIES OF COLD FRONTS COULD BRING SEVERAL ROUNDS OF SHOWERS
AND THUNDERSTORMS POSSIBLY CONTAINING HEAVY RAINFALL SUNDAY INTO
THE MID WEEK.

GENERALLY...DRY CONDITIONS ARE EXPECTED THROUGH AT LEAST EARLY
TODAY. HOWEVER...A WARM FRONT AND HIGHER MOISTURE CONTENT WILL
BRING SOME SCATTERED SHOWERS AND THUNDERSTORMS OVERNIGHT INTO SUNDAY
AND LASTING THROUGH TUESDAY.

THESE FRONTAL BOUNDARIES ASSOCIATED WITH A STRONG UPPER LEVEL
TROUGH WEST OF THE REGION COULD BRING INTERMITTENT SHOWERS AND
THUNDERSTORMS SUNDAY INTO THE MID WEEK PERIOD. LOCALLY HEAVY
RAINFALL IN THE HUMID AIR MASS COULD INCREASE THE THREAT FOR THE
POTENTIAL OF ISOLATED FLASH FLOODING WITH SOME IMPACTS ON THE MAIN
STEM RIVERS...SMALL STREAMS AND CREEKS. AT THIS POINT IT IS
DIFFICULT TO PINPOINT WHERE THE HEAVY RAINFALL WILL OCCUR...BUT
SOME LOCATIONS COULD RECEIVE SEVERAL INCHES OF RAINFALL FROM ANY
CONVECTION THAT REPEATEDLY MOVES OVER THE SAME AREAS.

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...BGM/SNYDER
NEAR TERM...SNYDER
SHORT TERM...BGM
LONG TERM...FRUGIS
AVIATION...FRUGIS
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA






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