Issued by NWS Albany, NY
Versions: 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --000 FXUS61 KALY 232102 AFDALY AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 402 PM EST MON NOV 23 2009 .SYNOPSIS... A WEAK LOW PRESSURE SYSTEM POSITIONED OFF THE MID ATLANTIC COAST WILL CONTINUE TO TRACK NORTHEASTWARD TONIGHT...AND WILL PASS EAST OF CAPE COD ON TUESDAY. A MOIST ONSHORE FLOW WILL RESULT IN MAINLY LIGHT RAIN OR DRIZZLE ACROSS PORTIONS OF THE REGION TONIGHT INTO EARLY TUESDAY MORNING...ESPECIALLY SOUTH AND EAST OF ALBANY. WEAK HIGH PRESSURE WILL BUILD IN ON TUESDAY...WITH TRANQUIL CONDITIONS PERSISTING INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 315 PM...A NORTHEAST ONSHORE FLOW RESULTING IN STRATUS CLOUDS ENCOMPASSING THE ENTIRE FORECAST AREA. THE MAIN SFC WAVE IS RATHER WEAK AND POSITIONED WELL TO OUR SOUTH AND EAST...HOWEVER A 1032MB AREA OF HIGH PRESSURE OVER SOUTHERN QUEBEC IS PROVIDING THE NORTHEAST FLOW. SO FAR MAIN EFFECT HAS BEEN INCREASING CLOUD COVER...HOWEVER THERE WILL BE A BETTER CHANCE FOR SOME RAIN TONIGHT AS WEAK ISENTROPIC LIFT ON THE 290K SURFACE LIFTS NORTHWARD ACROSS MAINLY SOUTHERN AREAS. FORECAST SOUNDINGS SHOWING DRY LAYER PERSISTING ALOFT WITH LOW LEVELS MOISTENING...SO THERE WILL BE SOME DRIZZLE AROUND AS WELL. WILL MENTION LIKELY POPS SOUTH AND EAST OF ALBANY...WITH CHANCE ACROSS CENTRAL AREAS. PORTIONS OF THE ADIRONDACKS WILL REMAIN DRY. FORCING WEAKENS AFTER MIDNIGHT...SO WILL GO WITH JUST CHANCE POPS FOR THE SECOND HALF OF THE NIGHT. DUE TO EXTENSIVE CLOUD COVER MIN TEMPS WILL BE AROUND 5-10 DEGREES ABOVE AVG. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 345 PM...NORTHEAST ONSHORE FLOW STILL EXPECTED TO PERSIST THROUGH TUE MORNING...ALTHOUGH WILL BE WEAKENING. ALSO...NO DISCERNIBLE FORCING WILL BE PRESENT SO WILL ONLY MENTION LOW CHANCE POPS IN THE MORNING...WHICH SHOULD BE EITHER LIGHT RAIN OR DRIZZLE. LACK OF ANY SUBSTANTIAL DRYING/MIXING WILL RESULT IN CLOUD COVER PERSISTING INTO THE AFTERNOON. SOME BREAKS IN THE CLOUDS MAY OCCUR VERY LATE IN THE DAY...BUT APPRECIABLE WARMING WILL LIKELY NOT TAKE PLACE SINCE SUNSET IS AROUND 430 PM. SO...WILL UNDERCUT BOTH MAV/MET GUIDANCE BY A FEW DEGREES FOR MAX TEMPS. TUE NIGHT AND WED SHOULD BE TRANQUIL WITH WEAK HIGH PRESSURE IN CONTROL. AGAIN...THE MAIN CHALLENGE WILL BE DETERMINING TEMPS WITH VARYING CLOUD COVER. IT APPEARS THAT THERE WILL BE A GRADUAL CLEARING TREND TUE NIGHT...WITH MOST AREAS SEEING APPRECIABLE BREAKS IN CLOUD COVER SO WILL LEAN TOWARDS COOLER MAV GUIDANCE FOR MIN TEMPS. WED WILL BE A MILD DAY WITH A RETURN SOUTHERLY FLOW DEVELOPING...AS HIGH PRESSURE DRIFTS TO OUR EAST. AT THIS POINT EXPECTING AT LEAST A MIX OF SUN AND CLOUDS AND TEMPS SHOULD RESPOND BY WARMING INTO THE LOWER TO MID 50S IN MOST LOCATIONS. A WEAKENING PIECE OF ENERGY BREAKING OFF FROM THE MAIN UPPER LEVEL TROF ACROSS THE MIDWEST...WILL LIFT NORTHEASTWARD ACROSS THE GREAT LAKES REGION WED NIGHT. NOT MUCH MOISTURE TO WORK WITH AND FORCING WILL BE WEAK...SO WILL ONLY MENTION CHANCE POPS WEST OF THE HUDSON RIVER. MIN TEMPS SHOULD BE ABOVE FREEZING ACROSS THE AREA WITH INCREASING CLOUDS AND A LIGHT SOUTHERLY BREEZE. && .LONG TERM /THURSDAY THROUGH MONDAY/...-- Changed Discussion --CONSENSUS CONTINUES TO BUILD REGARDING THE BLACK FRIDAY COASTAL STORM...THUS HAVE GONE WITH HPC`S SOLUTION. AT THE PRESENT TIME... IT APPEARS COLD AIR WILL BE TOO LIMITED TO WARRANT SNOW IN THE LOWER AND SOUTHERN REACHES OF OUR FORECAST AREA. INDEED...A LOOK AT SFC- 500 MB THICKNESSES INDICATES SUB-540 VALUES DON`T MOVE IN UNTIL VERY LATE IN THE GAME. THE EASTERLY WIND FLOW NORTH OF THE APPROACHING LOW THURSDAY LOW WILL ACTUALLY BE BRINGING IN SLIGHTLY MODIFIED AIR...SO THAT OVERNIGHT LOWS THURSDAY NIGHT ARE EXPECTED TO STAY ABOVE FREEZING EXCEPT IN THE ADIRONDACKS...WHERE A MOSTLY SNOW EVENT IS EXPECTED. TEMPERATURES WON`T LIFT MUCH ON FRIDAY WITH THE CLOUDS AND THE PRECIP...BUT HIGHS AROUND 40 IN THE HUDSON VALLEY ARE EXPECTED...WHICH ALMOST CERTAINLY SUGGESTS AN ALL-RAIN EVENT THERE THROUGH FRIDAY. ELSEWHERE...A MIX IS EXPECTED...AND IT WOULD BE DIFFICULT TO ENVISION ANY SIGNIFICANT ACCUMULATIONS EXCEPT IN THE MOUNTAINS...DESPITE THE GFS`S SUGGESTED SIGNIFICANT QPFS...WHICH TOTAL MAINLY BETWEEN AN INCH AND 1.50 INCHES FOR THE EVENT. SO... FOR MOST OF US...THIS IS NOW LOOKING LIKE MORE OF A SIGNIFICANT RAIN EVENT. BEYOND FRIDAY...SNOW WILL BECOME THE MORE DOMINANT WEATHER FEATURE ON SATURDAY AS THE LOW MOVES UP THROUGH MAINE AND THE CANADIAN MARITIMES...AND THE PRECIPITATION BECOMES LIGHTER AND MORE SHOWERY DUE TO A NORTHWESTERLY FLOW AND BACK-END LAKE ENHANCEMENT. POPS DECREASE RAPIDLY THROUGH SATURDAY NIGHT AS HIGH PRESSURE RIDGES IN FROM THE SOUTHEASTERN U.S....AND WINDS TURN MORE SOUTHWESTERLY. LOW PRESSURE FROM SOUTHWESTERN CANADA WILL TRACK TO THE GREAT LAKES THROUGH MONDAY...BRINGING OUR NEXT CHC FOR SIGNIFICANT PRECIP...AND THE ATMOSPHERE LOOKS COLD ENOUGH THAT THIS STORM COULD WIND UP BRINGING THE FIRST SIGNIFICANT SNOWS FOR MUCH OF THE REGION.-- End Changed Discussion --&& .AVIATION /21Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS AT KGFL AND KALB TO START THE PERIOD WILL DETERIORATE TO MVFR CIGS LATE THIS AFTERNOON. KPOU HAS FILLED IN WITH MVFR CIGS AS OF 1745Z. MVFR CLDS APPROACHING KGFL...HAVE INCLUDED TEMPO THROUGH 22Z. UPSTREAM SYSTEM ACROSS THE VIRGINIAS ARRIVES LATE TODAY INTO TONIGHT WITH AREAS OF DRIZZLE/LIGHT RAIN EXPECTED. THIS WILL RESULT IN PERSISTENT MVFR CIGS WITH MVFR VSBYS FOLLOWING THIS EVENING. THERE IS AN INCREASED POTENTIAL FOR IFR CONDITIONS OVERNIGHT...ESP AT KGFL WITH LIGHTER WINDS RESULTING IN IFR VSBYS. PRECIP EXPECTED TO ONLY BE VCSH AT KGFL WHILE MAIN SHIELD OF PRECIP WILL REACH KPOU THIS AFTERNOON AND KALB THIS EVENING. PRECIP WILL BE LIGHT BUT PERSIST THROUGH TUESDAY MORNING. CONDITIONS IMPROVING TO MVFR AT ALL TERMINALS BY LATE MORNING...FURTHER IMPROVING TO VFR IN THE AFTERNOON. WINDS WILL CONTINUE FROM THE N/NE AT 3-6KTS...DISSIPATING TO LGT AND VRB OVERNIGHT. LATE TUESDAY MORNING...WINDS WILL BE OUT OF THE N TO NE AROUND 5KTS. OUTLOOK... TUE PM-WED...VFR...NO SIG WX EXPECTED. WED NT-SAT...VFR TO MVFR/IFR...RAIN POSSIBLE THU THRU SAT. && .HYDROLOGY... RAINFALL AMOUNT ARE EXPECTED TO BE AROUND ONE TENTH OF AN INCH OR LESS ACROSS THE AREA TONIGHT...MAINLY SOUTH AND EAST OF ALBANY. THIS AMOUNT OF RAINFALL WILL HAVE VERY LITTLE IMPACT ON RIVERS AND STREAMS. THE NEXT CHANCE OF WIDESPREAD PRECIPITATION WILL BE FROM LATE THURSDAY NIGHT INTO THE WEEKEND...AS A POTENTIALLY STRONG STORM MAY IMPACT THE REGION. SIGNIFICANT PRECIPITATION IS POSSIBLE BUT PRECIP AMOUNTS AND TYPE ARE HIGHLY UNCERTAIN AT THIS TIME. 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...JPV NEAR TERM...JPV SHORT TERM...JPV LONG TERM...ELH AVIATION...KGS HYDROLOGY...JPV
