326  
FXUS61 KALY 210940  
AFDALY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE ALBANY NY  
440 AM EST TUE NOV 21 2017  
   
SYNOPSIS
 
 
FAIR AND MILD TODAY WITH TEMPERATURES RISING INTO THE  
UPPER 40S TO MID 50S AHEAD OF AN APPROACHING COLD FRONT. THE FRONT  
WILL SWEEP ACROSS THE REGION LATE TONIGHT INTO WEDNESDAY BRINGING  
SOME SNOW AND RAIN SHOWERS TO THE AREA. A MORE SEASONABLE AIR MASS  
WILL BE USHERED BACK IN WITH MAINLY FAIR WEATHER THEN EXPECTED  
THROUGH FRIDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
MILD, FAIR AND BREEZY TODAY AHEAD OF AN APPROACHING COLD FRONT.  
 
RIDGE AXIS, UPPER AND SURFACE, SHIFTS OFF THE COAST AND DEEP  
SOUTHWEST FLOW DEVELOPS ADVECTING WARMER AIR INTO THE REGION.  
EXPECTING HIGHS FROM THE UPPER 40S TO MID 50S; AROUND 10 DEGREES  
ABOVE NORMAL.  
 
WILL BECOME BREEZY AS THE GRADIENT PRESSURE TIGHTENS ACROSS THE  
REGION BETWEEN THE APPROACHING COLD FRONT AND DEPARTING RIDGE.  
SOUTH TO SOUTHWEST WINDS INCREASING TO 10 TO 20 MPH WITH GUSTS  
UP TO AROUND 30 MPH.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
 
 
FAIR WEATHER FOR THANKSGIVING.  
 
SHARP NORTHERN STREAM SHORT WAVE TROUGH WILL APPROACH TONIGHT  
AND MOVE OVERHEAD WEDNESDAY AS IT SHEARS OUT. IN THE MEANTIME,  
A PIECE OF SOUTHERN STREAM ENERGY AND ITS ASSOCIATED SURFACE LOW  
WILL REMAIN WELL OFF THE COAST AS IT QUICKLY HEADS NORTHEASTWARD  
OFF THE SOUTHEAST COAST.  
 
CLOUDS WILL BE IN THE INCREASE IN THE EVENING WITH CHANCES FOR  
SNOW AND RAIN SHOWERS INCREASING MAINLY AFTER MIDNIGHT AS THE  
COLD FRONT MOVES INTO THE REGION FROM THE WEST AND SOME MOISTURE  
IS DRAWN INTO THE REGION FROM THE COASTAL LOW. SHOWERS WILL  
TAPER OFF IN THE AFTERNOON LINGERING THE LONGEST ACROSS THE  
HIGHER TERRAIN. QPF AMOUNTS ARE EXPECTED TO BE LIGHT WITH ABOUT  
A QUARTER OF AN INCH ACROSS THE WESTERN ADIRONDACKS WITH LESSER  
AMOUNTS ELSEWHERE. LIGHT SNOWFALL ACCUMULATIONS OF 1-2 INCHES  
ARE EXPECTED ACROSS THE WESTERN ADIRONDACKS WITH LESS THAN AN  
INCH FOR AREAS GENERALLY ABOVE 1500 FEET.  
 
WITH THE PASSAGE OF THE COLD FRONT A MORE SEASONABLE AIR MASS  
WILL BE USHERED BACK IN ON BRISK AND GUSTY WEST-NORTHWEST WINDS.  
AREAS GENERALLY WEST OF THE HUDSON RIVER VALLEY WILL EXPERIENCE  
LITTLE IF ANY RISE IN TEMPERATURES WEDNESDAY WHILE EAST OF THE  
VALLEY TEMPERATURES WILL RISE SOME BEFORE DROPPING OFF LATER IN  
THE DAY.  
 
UPPER FLOW IS EXPECTED TO GO BRIEFLY FLAT WEDNESDAY NIGHT ACROSS  
THE REGION BETWEEN SHORT WAVES ROTATING ABOUT THE UPPER LOW  
OVER HUDSON'S BAY. THE NEXT SHORT WAVE TROUGH WILL NOT BE AS  
DEEP AND WILL PASS TO OUR NORTH ACROSS EASTERN CANADA THURSDAY  
NIGHT. WHILE AT THE SURFACE HIGHER PRESSURE BUILDS IN. THE  
RESULT WILL BE FAIR WEATHER WITH BELOW NORMAL TEMPERATURES  
WEDNESDAY NIGHT AND THANKSGIVING DAY. CHANCES FOR ANY SNOW  
SHOWERS ARE EXPECTED TO LIMITED TO PORTIONS OF THE WESTERN  
ADIRONDACKS THANKSGIVING NIGHT WITH SEASONABLE LOWS AS WINDS  
SHIFT TO THE SOUTHWEST.  
 

 
   
LONG TERM /FRIDAY THROUGH MONDAY/
 
 
GOOD MODEL AGREEMENT THAT THE PROGRESSIVE PATTERN CONTINUES INTO THE  
LONG TERM PERIOD WITH THE MEAN HUDSON BAY UPPER LOW REMAINING  
DOMINANT. DISTURBANCES PINWHEELING AROUND THE LOW HAVE FAVORED A  
STORM TRACK ALONG OR NORTH OF THE ST. LAWRENCE VALLEY RECENTLY, AT  
IT APPEARS THAT WILL CONTINUE TO BE THE CASE. LITTLE EVIDENCE AT  
THIS TIME THAT ANY SOUTHERN STREAM ENERGY WILL PHASE WITH THE  
NORTHERN STREAM.  
 
FRIDAY APPEARS TO BE A TRANQUIL AND SEASONABLE DAY. UPPER HEIGHTS  
WILL RISE IN CONJUNCTION WITH SHORTWAVE ENERGY TRACKING ACROSS THE  
NORTHERN GREAT LAKES REGION. ATTENDANT SURFACE LOW LOOKS TO TRACK  
WELL NORTH INTO NORTHERN QUEBEC, DRAGGING ITS FRONT ACROSS THE  
FORECAST AREA ON SATURDAY. MIDLEVEL FORCING WILL AUGMENT THE FRONT  
AND RESULT IN SHOWER POTENTIAL, BUT IT APPEARS TO BE A LOW-QPF  
SCENARIO ATTM GIVEN LACK OF MOISTURE SOURCE AND PROGRESSIVE FORCING.  
GIVEN THE STORM TRACK, A P-TYPE OF RAIN IS FAVORED OVER MOST AREAS  
SATURDAY, WITH A TENDENCY TO MIX WITH SNOW WITH TIME LATER SATURDAY  
INTO SATURDAY NIGHT, MAINLY AT ELEVATION. ADDITIONAL SHORTWAVE  
ENERGY IS FORECAST TO CARVE OUT A DEEPENING UPPER TROUGH OVER THE  
GREATER NORTHEAST SUNDAY AND MONDAY. H850 TEMPS PROGGED TO FALL TO -  
10 TO -15C, OR POSSIBLY A BIT LOWER AS SHOWN BY THE 00Z ECMWF, BY  
SUNDAY NIGHT. THESE VALUES ARE 1 TO 2 SD BELOW NORMAL. THIS WILL  
ALLOW FOR A LAKE RESPONSE SUNDAY INTO SUNDAY NIGHT, WITH FLOW  
TRAJECTORIES VEERING FROM NW TO NNW. SOME SYNOPTIC FORCING WITH THE  
REINFORCING WAVE COULD CARRY SOME SHOWERS FURTHER INLAND THAN THE  
NORMAL LAKE EFFECT/UPSLOPE FAVORED AREAS SUNDAY. IT APPEARS HEIGHT  
RISES BUILD IN MONDAY, ALLOWING LAKE EFFECT TO DIMINISH.  
 

 
   
AVIATION /09Z TUESDAY THROUGH SATURDAY/
 
 
CLOUDS HAVE SHIFTED NORTH OF THE TERMINALS AS UPPER LEVEL  
HEIGHTS RISE AND A WARMER AIRMASS ADVECTS INTO THE REGION. THIS  
WILL ENSURE VFR CONDITIONS THROUGHOUT THE TAF PERIOD. ASIDE FROM  
A FEW HIGH CLOUDS, MAINLY CLEAR SKIES ARE EXPECTED TO PREVAIL.  
 
WINDS TONIGHT WILL BE NEARLY CALM TO SOUTHERLY AT AROUND 8 KT OR  
LESS. MARGINAL CONDITIONS FOR LOW-LEVEL WIND SHEAR, BUT LLWS WAS  
ADDED TO THE TAF SITES INTO MID-MORNING EXCEPT FOR KALB WHERE  
SOUTHERLY FLOW WILL BE STRONGEST. WITH DIURNAL MIXING, WINDS  
MAY GET A BIT GUSTY TUESDAY LATE MORNING INTO THE AFTERNOON,  
WITH GUSTS OF 20-30 KT POSSIBLE, STRONGEST AT KALB. WINDS WILL  
DIMINISH TUESDAY EVENING.  
 
OUTLOOK...  
 
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
THANKSGIVING DAY: NO OPERATIONAL IMPACT. NO SIG WX.  
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.  
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.  
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.  
 

 
   
FIRE WEATHER
 
 
SOUTH TO SOUTHWEST WINDS 10 TO 20 MPH WITH GUSTS UP TO AROUND  
30 MPH AT TIMES TODAY WITH MINIMUM RELATIVE HUMIDITY VALUES  
IN THE 30S THIS AFTERNOON.  
 
FAIR AND MILD TODAY AHEAD OF AN APPROACHING COLD FRONT. THE FRONT  
WILL SWEEP ACROSS THE REGION LATE TONIGHT INTO WEDNESDAY BRINGING  
SOME SNOW AND RAIN SHOWERS TO THE AREA. A MORE SEASONABLE AIR MASS  
WILL BE USHERED BACK IN WITH MAINLY FAIR WEATHER THEN EXPECTED  
THROUGH FRIDAY.  
 

 
   
HYDROLOGY
 
 
NO HYDROLOGIC PROBLEMS ARE EXPECTED THIS WEEK.  
 
FAIR AND MILDER WEATHER TODAY WITH SOME RAIN AND SNOW SHOWERS  
LATE TONIGHT INTO WEDNESDAY AS A COLD FRONT CROSSES THE REGION.  
QPF AMOUNTS ARE EXPECTED TO BE LIGHT WITH ABOUT A QUARTER OF AN  
INCH ACROSS THE WESTERN ADIRONDACKS WITH LESSER AMOUNTS ELSEWHERE.  
 
WITH THE PASSAGE OF THE COLD FRONT A MORE SEASONABLE AIR MASS  
WILL BE USHERED BACK IN WITH MAINLY FAIR WEATHER THEN EXPECTED  
THROUGH FRIDAY.  
 
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...IAA  
NEAR TERM...IAA  
SHORT TERM...IAA  
LONG TERM...THOMPSON  
AVIATION...THOMPSON  
FIRE WEATHER...IAA  
HYDROLOGY...IAA  
 
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