October 25, 2012 Forecast Discussion

000
FXUS61 KALY 252356
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
756 PM EDT THU OCT 25 2012

.SYNOPSIS…
HIGH PRESSURE ANCHORED OVER THE GULF OF MAINE WILL CONTINUE TO
CONTROL OUR WEATHER THROUGH EARLY SATURDAY. A COLD FRONT WILL SLOWLY
APPROACH FROM THE WEST SATURDAY AND SUNDAY. HURRICANE SANDY MAY
THREATEN OUR REGION THE BEGINNING OF NEXT WEEK. PLEASE REFER TO THE
NATIONAL HURRICANE CENTER FOR THE OFFICIAL FORECAST TRACK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/…
AS OF 755 PM EDT…CLOUDS STILL HANGING TOUGH OVER THE HUDSON
VALLEY…AND HAVE ACTUALLY EXPANDED NORTH AND WEST INTO THE MOHAWK
VALLEY AND SOUTHEAST ADIRONDACKS. ALSO…THE HIGHER TERRAIN OF THE
EASTERN CATSKILLS AND LITCHFIELD HILLS HAVE A SOLID STRATUS DECK.

THEREFORE HAVE ADJUSTED THE SKY GRIDS TO REFLECT CLOUDIER
CONDITIONS ACROSS THESE AREAS…AND EXPECTING THE LOW STRATUS TO
SLOWLY BUILD NORTHWARD THROUGH THE EVENING AND INTO THE OVERNIGHT
HOURS. THE ONLY EXCEPTION WHERE THE STRATUS MAY NOT REACH IS THE
WESTERN ADIRONDACKS.

WITH THE THICK CLOUDS AND A LIGHT SOUTHERLY BREEZE…TEMPERATURES
WILL REMAIN MILD…WITH LOWS GENERALLY IN THE UPPER 40S TO LOWER
50S.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/…
RIDGING ALOFT WILL ADVECT DRIER AIR INTO OUR REGION ON FRIDAY. AFTER
MORNING CLOUDS…FINALLY SOME SUNSHINE SHOULD SHINE EVERYWHERE BY
AFTERNOON. ASSUMING THIS…TEMPERATURES WILL JUMP 65 TO 70 ACROSS
MOST OF THE REGION…ALONG WITH A SOUTH TO SOUTHEAST WIND 5 TO 15
MPH. THIS WILL BE OUR NICEST DAY OF THE NEXT 5-7.

FRIDAY NIGHT INTO SATURDAY…A COLD FRONT WILL SLOWLY INCH INTO OUR
REGION. INITIALLY IT WILL BE AN ANAFRONT (THE WIND FIELD PARALLELS
THE FRONT) KEEPING THE RAIN ALONG OR BEHIND THE FRONT. SINCE THE
FRONT MIGHT NOT EVEN MAKE IT PAST THE HUDSON VALLEY THROUGH THIS
TIME FRAME…WE TRIMMED BACK THE POPS EVEN MORE. WE INTRODUCE SLIGHT
CHANCES OF SHOWERS LATE FRIDAY ACROSS OUR ADIRONDACKS ONLY…AND IT
IS NOT UNTIL LATE SATURDAY UNTIL LOW CHANCES OF SHOWERS REACH THE
HUDSON VALLEY. THERE IS PRETTY GOOD SURFACE CONVERGENCE WITH FRONT
AND MOISTURE AHEAD OF IT SO SCATTERED TO NUMEROUS SHOWERS ARE A GOOD
BET…MAINLY WEST OF THE HUDSON VALLEY. FURTHER EAST…CHANCES
REMAIN LOW TO SLIGHT ALL DAY LONG SATURDAY.

TEMPERATURES ACROSS MOST OF THE AREA LOOK TO REMAIN THROUGH THIS
TIME PERIOD. HOWEVER…FRIDAY NIGHT MIGHT ACTUALLY FEATURE LITTLE OR
NO WIND AND SOME BREAKS IN THE CLOUDS…SO TEMPERATURES MIGHT
ACTUALLY BE SLIGHTLY COOLER COMPARED TO TONIGHT BUT STILL WELL ABOVE
NORMAL. LOOK FOR LOWS 45-50 FRIDAY NIGHT AND 65-70 AGAIN ON
SATURDAY…EXPECT AROUND 60 ACROSS THE ADIRONDACKS.

TIMING OF THE APPROACH OF THE FRONT IS IN QUESTION…ESPECIALLY
WITH UPPER RIDGING BUILDING OFF THE NORTHEASTERN U.S. AND SE
CANADA…WHICH SHOULD EVENTUALLY INFLUENCE THE MOVEMENT OF THE
TROPICAL SYSTEM. GUIDANCE AND ENSEMBLES AT THIS POINT SUGGEST
A SLOWING FRONT THAT MAY BECOME STATIONARY IN WESTERN OR CENTRAL
NY. SUGGESTING SCATTERED SHOWERS WITH HIGHS IN THE MID TO UPPER
60S AS THE AXIS OF WARMEST BOUNDARY LAYER TEMPERATURES COULD BE
JUST EAST OF OUR REGION. SOME UPPER 50S IN THE SOUTHERN
ADIRONDACKS WHERE CLOUDS AND BETTER COVERAGE OF SCATTERED SHOWERS
COULD KEEP TEMPERATURES DOWN A BIT. SCATTERED SHOWERS AND LOWS IN
THE 40S TO AROUND 50 SATURDAY NIGHT.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/…
THE EXTENDED FORECAST HAS BEEN POPULATED WITH HPC GUIDANCE
THROUGHOUT BASED ON THE UNCERTAINTY WITH THE TRACK OF SANDY. IT
MUST BE EMPHASIZED THAT THEIR IS A WIDE RANGE OF MEDIUM RANGE
DETERMINISTIC AND ENSEMBLES SOLUTIONS AT THIS TIME IN THE MONDAY TO
WEDNESDAY TIME FRAME. HOWEVER…THERE APPEARS TO BE ENOUGH OF A
CONSENSUS FOR AN IMPACT IN THE ALY FCST AREA IN THE EARLY TO MIDDLE
PORTION OF NEXT WEEK.

THE HPC GUIDANCE LEANS MORE TO A GFS CANADIAN GGEM SOLUTION WITH AN
INTENSE TROPICAL/SUBTROPICAL CYCLONE IMPACTING NY AND NEW ENGLAND
LATE MONDAY THROUGH WEDNESDAY. THE CYCLONE COULD BE IN THE 940-950
HPA RANGE AS IT SLIDES FROM EAST TO WEST JUST SOUTH OF LONG ISLAND
AND COASTAL SRN NEW ENGLAND. NOW…THE ECMWF CONTINUES FOR THE
SECOND RUN TO HAVE AN INTENSE SUB-930 HPA SFC CYCLONE SLAM INTO THE
CHESAPEAKE BAY REGION MON/MON PM. THE HIRES ECMWF IS A 928 HPA LOW
!!! THIS DEEP AND INTENSE LOW PRESSURE SYSTEM WOULD BE HISTORICAL
IF IT DEEPENS AND INTENSIFIES TO THAT MINIMUM PRESSURE. THE ECMWF
WOULD SHOW DRAMATIC FILLING…OR CYCLO LYSIS WITH THE STORM BEING A
964 HPA LOW OVER NRN VA IN 12+HOURS. THE ECMWF WOULD HAVE A LESSER
IMPACT THAN THE HPC/GFS/CAN GGEM/GEFS SCENARIO…BUT STILL SOME
PERIODS OF RAIN AND WIND MAY OCCUR MONDAY INTO WEDNESDAY.

IT SHOULD BE NOTED 6-HR UPPER AIR LAUNCHES AT ALY CONTINUE UNTIL 12Z
TUE TO ANALYZE THE UPSTREAM LONG-WAVE UPPER TROUGH OVER THE WRN TWO
THIRDS OF THE LOWER 48 THAT WILL CAPTURE SANDY AROUND MONDAY. THE
UPPER AIR DATA WILL ALSO HELP SAMPLE FOR SANDYS IMPACT AS IT HEADS
POLEWARD.

LEANING TOWARDS THIS HPC SOLUTION…THE IMPACT PERIOD FOR STRONG
WINDS AND PERIODS OF HVY RAINFALL WOULD BE MONDAY AFTERNOON INTO
WEDNESDAY. THE LATEST 12Z GEFS ARE CONSISTENT WITH THE 00Z/06Z GEFS
WITH THE LOW-LEVEL H850 EASTERLY WIND ANOMALIES INCREASING TO IN
EXCESS OF 5 STANDARD DEVIATIONS ABOVE NORMAL !!! WE COULD HAVE A
PERIOD FROM MONDAY NIGHT THROUGH TUESDAY OF EASTERLY OR -U WIND
ANOMALIES OF 3 TO 5+ STANDARD DEVIATIONS ABOVE NORMAL. PWATS WOULD
ALSO BE IN THE 1 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. PERIODS OF
MODERATE TO HVY RAIN COULD OCCUR FOR MORE THAN A 24-HR PERIOD MONDAY
NIGHT THROUGH TUESDAY. LIKELY POPS WERE UTILIZED FOR MUCH OF THIS
TIME FRAME…WITH THE PHRASING RAIN…HEAVY AT TIMES. THE WINDS WILL
LIKELY INCREASE IN TIME…BUT CURRENT FORECASTS HAVE SE TO NE WINDS
OF 15 TO 25 MPH WITH GUSTS AT LEAST TO 40 MPH MAY BE POSSIBLE OVER
THE REGION. IT IS LIKELY THESE WINDS WILL BE INCREASED DEEPENING ON
THE OFFICIAL TRACK OF NHC…AND WHERE ANY EXTRATROPICAL TRANSITION
OCCURS…IF IT OCCURS.

OUR HWOALY MENTIONS THE POTENTIAL THREAT OF STRONG TO DAMAGING WINDS
MONDAY INTO WEDNESDAY…WITH HEAVY RAIN OR FLOODING POSSIBLE. SEE
THE HYDRO DISCUSSION…AS SOME OF THE MMEFS NAEFS SHOW AT LEAST
MINOR FLOODING OVER PARTS OF THE HSA. IF CONFIDENCE
INCREASES…THEN WATCHES…WARNINGS OR ADVISORIES WILL BE ISSUED
LATER IN TIME. THE CATSKILLS MAY RECEIVE SEVERAL INCHES OF RAINFALL
DUE TO THE INTENSE E/SE FLOW /POSSIBLY IN EXCESS OF 5 INCHES BASED
ON THE GFS/. MOST OF THE REST OF THE FCST AREA COULD GET A FEW
INCHES OF RAIN.

A CONTINUING WIDE RANGE OF SOLUTIONS ARE STILL POSSIBLE…AS WE MAY
STILL BE DEALING WITH IMPACTS FROM THE SIGNIFICANT STORM SYSTEM
ESPECIALLY IN TERMS OF RAINFALL ON WEDNESDAY. MODEL GUIDANCE TRENDS
GENERALLY SHOWING THE LOW CENTER FILLING DURING THE DAY
WEDNESDAY…HOWEVER THERE ARE STILL SOME MODELS SHOWING A DEEP LOW
MOVING THROUGH THE REGION WHILE OTHERS HAVE SIGNIFICANT WEAKENING
TAKING PLACE. THE POSITION IS STILL VERY UNCERTAIN…ESPECIALLY IN
THE DAYS 6-7 FORECAST TIME PERIOD. WILL STILL MENTION CHANCE POPS
FOR RAIN ON WEDNESDAY…ALTHOUGH WIND COULD STILL BE AN ISSUE
DEPENDING ON HOW DEEP THE LOW ENDS UP BEING. WEDNESDAY NIGHT INTO
THURSDAY…WE COULD STILL BE AFFECTED BY THE SLOWLY DEPARTING UPPER
LEVEL LOW BUT WITH LESS SIGNIFICANT IMPACTS BY THIS TIME FRAME. WILL
STILL MENTION CHANCE POPS WITH COOLING TEMPS AS WE COULD START
SEEING COLD AIR ADVECTION FROM THE SOUTHWEST.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/…
LOW STRATUS CLOUDS NEVER REALLY CLEARED OUT OF KALB/KPOU
TODAY…ALTHOUGH KGFL/KPSF MANAGED SOME BREAKS LATE TODAY.
HOWEVER…SINCE SUNSET LOW STRATUS DECK HAS BEGUN EXPANDING
GRADUALLY NORTHWARD AND SHOULD REDEVELOP AT KPSF AND KGFL
THROUGHOUT THE EVENING. IT WILL TAKE LONGER AT KGFL. KALB/KPOU
SHOULD REMAIN SOCKED IN WITH THE LOW STRATUS. SOLID MVFR
CONDITIONS…MAINLY FOR CIGS…ARE EXPECTED THROUGH THE OVERNIGHT
AND MORNING HOURS. SOME BR IS POSSIBLE BUT THICK CLOUD COVER
SHOULD PRECLUDE THICK FOG FORMATION. CIGS SHOULD REMAIN MVFR BUT
COULD APPROACH IFR TOWARDS MORNING ALTHOUGH CONFIDENCE IS LOW.

DUE TO LOW SUN ANGLE AND A PERSISTENT WEAK SOUTHERLY
FLOW…EXPECTING STRATUS WILL TAKE A LONG TIME TO ERODE. WILL
MENTION MVFR CIGS UNTIL 16Z AT ALL TERMINALS FOR NOW. CLOUDS COULD
LINGER INTO THE EARLY AFTERNOON TOO. THEN VFR CONDITIONS SHOULD
PREVAIL THROUGH 00Z SATURDAY AS A RIDGE OF HIGH PRESSURE REMAINS
IN CONTROL.

OUTLOOK…
FRI NT-SAT AM…MVFR/IFR…LOW STRATUS CLOUDS LIKELY.
SAT PM…VFR. SLIGHT CHC -SHRA.
SAT NT-SUN…MVFR/IFR…LOW STRATUS CLOUDS LIKELY.
SUN NT-MON…MVFR/IFR WITH CHC RAIN SUN NT…THEN LIKELY MON.
BECOMING WINDY.
TUE…MVFR/IFR WITH RA/+RA AND VERY WINDY CONDITIONS.

&&

.FIRE WEATHER…
FIRE WEATHER RELATED CONCERNS WILL BE MINIMAL OVER THE NEXT
SEVERAL DAYS DUE TO LIGHT WINDS AND PERSISTENT HIGH RELATIVE
HUMIDITIES. REFER TO LATEST FWFALY FOR MORE SPECIFIC DETAILS.

&&

.HYDROLOGY…
NO MAJOR HYDROLOGICAL PROBLEMS ARE EXPECTED THROUGH AT LEAST
SATURDAY.

LITTLE OR NO RAIN EXPECTED THROUGH EARLY SATURDAY. LATER SATURDAY
INTO SUNDAY THE CHANCE OF SHOWERS INCREASES AS A SLOW MOVING COLD
FRONT HEADS OUR WAY.

THEN…WE TURN OUR ATTENTION TO SANDY (OR A HYBRID STORM) AS WE HEAD
INTO EARLY NEXT WEEK. THE POTENTIAL IS THERE FOR SIGNIFICANT RAIN
BUT THIS FAR OUT…WE CANNOT REALLY DETERMINE HOW MUCH WILL
ULTIMATELY FALL. THERE ARE SIGNALS THAT THE HEAVIEST RAIN MIGHT
FALL ACROSS OUR SOUTHERN AREAS BUT AGAIN THIS IS NOT ETCHED IN
STONE. THE IS LOW CONFIDENCE THAT MINOR TO MODERATE FLOODING COULD
TAKE PLACE ACROSS PORTIONS OF OUR REGION…ESPECIALLY TO THE SOUTH
OF ALBANY. HOWEVER…THE EXACT TRACK OF HURRICANE SANDY WILL
DETERMINE HOW EXTENSIVE FLOODING COULD BE.

STAY TUNED.

&&

.ALY WATCHES/WARNINGS/ADVISORIES…
CT…NONE.
NY…NONE.
MA…NONE.
VT…NONE.

&&

$$
SYNOPSIS…HWJIV
NEAR TERM…HWJIV/JPV
SHORT TERM…HWJIV
LONG TERM…JPV/WASULA
AVIATION…JPV
FIRE WEATHER…HWJIV/NAS
HYDROLOGY…HWJIV/NAS

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