951  
FXUS61 KALY 180235  
AFDALY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE ALBANY NY  
935 PM EST SUN FEB 17 2019  
   
SYNOPSIS
 
 
LOW PRESSURE WILL APPROACH FROM THE OHIO VALLEY TONIGHT BRINGING  
SNOW TO EASTERN NEW YORK AND WESTERN NEW ENGLAND. THE STORM  
SYSTEM WILL REDEVELOP EAST OF NEW JERSEY AND PASS SOUTH OF LONG  
ISLAND TOMORROW MORNING INTO THE AFTERNOON BRINGING A LIGHT TO  
MODERATE SNOW ACCUMULATION ACROSS THE AREA. THE SNOW WILL TAPER  
TO SCATTERED SNOW SHOWERS AND FLURRIES BY THE LATE AFTERNOON  
INTO THE EARLY EVENING, AS HIGH PRESSURE WILL BRING MAINLY DRY  
AND SEASONABLY COLD TEMPERATURES MONDAY NIGHT THROUGH TUESDAY  
BEFORE ANOTHER STORM SYSTEM ARRIVES LATE WEDNESDAY INTO  
THURSDAY.  
 

 
   
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
 
 
WINTER WEATHER ADVISORY IN EFFECT THROUGH 4 PM EST MONDAY FOR  
THE MOHAWK VALLEY, GREATER CAPITAL REGION, HELDERBERGS, MID  
HUDSON VALLEY, TACONICS, EASTERN CATSKILLS, BERKSHIRES AND  
LITCHFIELD COUNTY, CONNECTICUT...  
 
AS OF 935 PM EST...SNOW HAS DEVELOPED ACROSS FOR MUCH OF THE  
AREA SOUTH OF ALBANY AND IS GRADUALLY SPREADING NORTHWARD.  
SIGNIFICANT DRY LAYER IN LOW LEVELS EVIDENT ON 00Z KALY  
SOUNDING HAS PREVENTED SNOW FROM REACHING THE GROUND LOCALLY IN  
THE CAPITAL DISTRICT TO THIS POINT. TEMP-DEWPOINT SPREADS STILL  
AROUND 10-15F FROM AROUND I-90 NORTHWARD LATE THIS EVENING, SO  
IT WILL TAKE SOME TIME TO SATURATE THE COLUMN. STILL LOOKING AT  
ONSET OF SNOW AROUND 10-11 PM IN THE MOHAWK VALLEY/CAPITAL  
DISTRICT, AND ADIRONDACKS/SARATOGA LAKE GEORGE REGION INTO  
SOUTHERN VT BETWEEN 12-2 AM.  
 
MUCH OF THE GREAT LAKES REGION, AND THE NORTHEAST IS LOCATED  
NEAR A MID AND UPPER LEVEL JET CONFLUENT REGION. A STRONG MID  
AND UPPER LEVEL TROUGH IS CENTERED OVER THE CENTRAL CONUS WITH A  
CLOSED NORTHERN STREAM H500 CIRCULATION WEAKENING AND OPENING  
UP, WHILE A SOUTHERN STREAM SHORT-WAVE LIFTS NORTHEAST FROM THE  
TN VALLEY. THIS DISTURBANCE SHEARS OUT, BUT SOME GOOD OVER  
RUNNING SNOWFALL SETS UP WITH PLENTY OF LOW-LEVEL COLD AIR IN  
PLACE AND THE ISENTROPIC LIFT INCREASING ON THE 285K SFC WITH A  
MODEST LOW-LEVEL JET AHEAD OF THE PRIMARY SFC LOW AND ITS WARM  
FRONT/INVERTED SFC TROUGH.  
 
THE FORECAST AREA WILL BE LOCATED NEAR THE LEFT EXIT REGION OF  
NEARLY A 125 KT H500 JET STREAK. SOME WARM ADVECTION PCPN  
SHOULD BE COMMENCING BETWEEN 9 PM AND MIDNIGHT INITIALLY SOUTH  
AND WEST OF THE CAPITAL REGION, AND THEN OVERSPREADING THE  
ENTIRE AREA. IT WILL TAKE A LITTLE TIME FOR COLUMN TO SATURATE.  
THE LOW-LEVEL H850-700 FGEN STRENGTHENS OVERNIGHT (ESPECIALLY ON  
THE NAM) AS THE PRIMARY LOW MOVES TOWARD WESTERN/CENTRAL PA/NY,  
AND THEN REDEVELOPS EAST/SOUTHEAST OF NJ. SNOWFALL RATES COULD  
REACH A HALF TO THREE QUARTERS OF AN INCH AN HOUR BETWEEN  
ROUGHLY MIDNIGHT AND 6 AM BASED ON THE LATEST 12 HREFS. WE  
INCREASED THE POPS TO CATEGORICAL VALUES AT THIS TIME. WE  
FOLLOWED THE 12Z HREFS ON THE INCREASED RATES DURING THIS TIME  
FRAME. OVERALL, A COUPLE OF INCHES OF SNOWFALL SHOULD BE ON THE  
GROUND IN MOST LOCATIONS (THE ONE EXCEPTION MAY BE PORTIONS OF  
THE SOUTHERN ADIRONDACKS, AND PORTIONS OF THE LAKE GEORGE  
REGION) BY DAYBREAK WITH 2 TO 4 INCHES FROM THE CAPITAL  
REGION/MOHAWK VALLEY SOUTHWARD. WE LEANED FAIRLY CLOSE TO THE  
WPC QPF, WHICH WAS IN LINE MORE WITH THE 12Z NAM/ECMWF/GFS. THE  
GFS TENDED TO BE THE LIGHTEST.  
 
PWATS ARE NOT HIGHLY ANOMALOUS WITH THIS SYSTEM WITH THE LATEST  
GEFS GRAZING SOUTHERN AREAS WITH SLIGHTER GREATER THAN NORMAL  
VALUES. THE H850 LOW-LEVEL JET IS NOT HIGHLY ANOMALOUS WITH THE  
+V-COMPONENT WIND ANOMALIES /SOUTHERLIES/ INCREASING TO +1 TO  
+2 STD DEVS ABOVE NORMAL TRANSPORTING SOME GULF OR ATLANTIC  
MOISTURE INTO THE REGION. THE 12Z GFS/NAM INDICATE A  
SOUTHWESTERLY LLJ OF 25-30 KTS OVERNIGHT. THE PCPN EFFICIENCY IS  
NOT EXPECTED TO BE DRAMATIC AS THE DENDRITIC GROWTH ZONE IN THE  
REMAINS HIGH UP, NOT INTERSECTING THE UPWARD VERTICAL MOTION OR  
OMEGA WELL. LOWS TONIGHT WILL LIKELY BE DUE TO WET BULBING WITH  
LOWS IN THE TEENS NORTH AND WEST OF THE CAPITAL REGION, AND  
LOWER TO MID 20S TO THE SOUTH AND EAST.  
 

 
   
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
 
 
WINTER WEATHER ADVISORY UNTIL 4 PM EST MON FROM THE MOHAWK  
VALLEY, GREATER CAPITAL REGION, HELDERBERGS, MID HUDSON VALLEY,  
TACONICS, EASTERN CATSKILLS, BERKSHIRES AND LITCHFIELD COUNTY,  
CONNECTICUT...  
 
TOMORROW...THE SNOW WILL BE CONTINUING THROUGH THE LIMITED  
HOLIDAY MORNING COMMUTE WITH SOME SNOW COVERED SLICK ROADS, AND  
REDUCED VISIBILITIES. THERE ARE SOME INDICATIONS FROM THE  
GUIDANCE, THAT A DRY SLOT MAY GET CLOSE TO THE SOUTHEAST  
CATSKILLS, AND THE MID- HUDSON VALLEY AFTER DAYBREAK, AS THE  
PCPN INTENSITY MAY LET UP. ALSO, THE NAM BUFKIT MODEL SOUNDINGS  
ARE INDICATING THAT WE COULD LOSE THE ICE NUCLEI IN THE CLOUDS  
AFTER 12Z NEAR KPOU. THE BEST ISENTROPIC LIFT AND LOW-LEVEL  
FGEN SHIFTS EAST TO NORTHEAST OF THE REGION. THERE COULD BE A  
BRIEF PERIOD OF SNOW MIXING WITH OR CHANGING TO FREEZING RAIN  
NEAR THE I-84 CORRIDOR, SO WE HAVE A LIGHT GLAZE OF ICE OF A  
COATING TO A HUNDREDTH IN THE FORECAST FOR SOUTHERN DUTCHESS,  
ULSTER, AND LITCHFIELD COUNTIES.  
 
PERIODS OF LIGHT SNOW SHOULD CONTINUE FURTHER NORTH DUE TO AN  
INVERTED SFC TROUGH NORTHWEST OF THE SECONDARY COASTAL WAVE  
FORMING NEAR SOUTHERN NJ AND PASSING SOUTH OF LONG ISLAND. THE  
MID AND UPPER LEVEL JET DYNAMICS WILL ALSO REMAIN FAVORABLE FOR  
THE SNOW PERSISTING INTO THE EARLY AFTERNOON COUPLED WITH SOME  
VORTICITY ADVECTION ASSOCIATED WITH THE NORTHERN STREAM SHORT-  
WAVE. TOTAL QPF CAME UP SLIGHTLY INTO THE 0.20-0.40" RANGE AND  
WE INCREASED SNOW AMOUNTS A COUPLE OF INCHES. WE ARE EXPECTING 3  
TO 6 INCHES OF SNOW IN THE ADVISORY AREA. THE HIGHEST TOTALS  
WILL LIKELY BE AROUND 6 INCHES IN THE EASTERN CATSKILLS,  
HELDERBERGS, AND A FEW LOCATIONS IN THE BERKSHIRES. NOT  
WIDESPREAD ENOUGH FOR A WARNING. FURTHER NORTH, WE HAVE 2 TO 4"  
IN THE SOUTHERN ADIRONDACKS, LAKE GEORGE/NORTHERN SARATOGA  
REGION, AND SOUTHERN VT. A FEW LOCATIONS IN THE SOUTHERN GREENS  
COULD GET AROUND 4", BUT IT WAS NOT WIDESPREAD ENOUGH FOR AN  
ADVISORY. WE USED SNOW TO LIQUID RATIOS A LITTLE ABOVE CLIMO IN  
THE 12-17:1 RANGE. IF AMOUNTS EDGE UP FURTHER NORTH, THEN THE  
ADVISORY MAY HAVE TO BE EXPANDED LATER. THE 12Z HREFS MEAN 24-HR  
SNOWFALL WENT KIND OF HIGH IN THE 6-8" OR SO RANGE IN PARTS OF  
THE HELDERBERGS, EASTERN CATSKILLS, SCHOHARIE VALLEY, AND THE  
WESTERN MOHAWK VALLEY. WE THINK THE LOW END OF THE RANGE COULD  
BE HIT, BUT BASED ON THE TRACK OF THE SECONDARY LOW AND THE  
LIMITED MOISTURE THIS SEEMED KIND OF HIGH. WE ALSO EXTENDED THE  
END TIME FOR THE ADVISORY TO 4 PM AS SNOW IN THE THE MID/UPPER  
DEFORMATION ZONE COULD LINGER A BIT BETWEEN 1-4 PM ESPECIALLY  
FROM THE CAPITAL REGION/TACONICS EASTWARD. IF THE SNOW ENDS  
SOONER, THEN IT CAN BE CANCELED. HIGH TEMPS WILL RANGE FROM THE  
MID AND UPPER 20S NORTH AND WEST OF THE CAPITAL REGION TO THE  
LOWER TO MID 30S MAINLY FROM THE TRI CITIES SOUTH AND EAST.  
 
MONDAY NIGHT...LOW PRESSURE MOVES FURTHER INTO THE NORTH  
ATLANTIC SOUTH AND EAST OF NOVA SCOTIA. THE H500 TROUGH AXIS  
MOVES DOWN STREAM, AS WELL AS A SFC TROUGH. COLD ADVECTION  
OCCURS OVERNIGHT WITH H850 TEMPS FALLING TO -13C TO -17C FROM  
THE CAPITAL REGION NORTHWEST, AND -9C TO -13C SOUTH AND EAST.  
THE SKIES SHOULD BECOME PARTLY CLOUDY TO MOSTLY CLEAR. SOME  
NARROW MULTIBANDS OF LAKE EFFECT SNOW MAY GRAZE THE WESTERN  
MOHAWK VALLEY, NORTHERN CATSKILLS, AND WESTERN ADIRONDACKS IN  
THE NORTHWEST FLOW. LOWS WILL BE IN THE SINGLE DIGITS TO LOWER  
TEENS, THOUGH SOME BELOW ZERO READINGS ARE POSSIBLE OVER THE  
SOUTHERN ADIRONDACKS. THE NORTHWEST WINDS COUPLED WITH THE COLD  
TEMPS MAY PRODUCE WIND CHILLS BELOW ZERO OVER THE HIGHER  
TERRAIN.  
 
TUESDAY-TUESDAY NIGHT...A BROAD SFC ANTICYCLONE BUILDS EASTWARD  
FROM THE NORTHERN PLAINS AND THE UPPER MIDWEST EASTWARD ACROSS  
THE GREAT LAKES REGION INTO THE NORTHEAST. SOME LINGERING LAKE  
EFFECT SNOW SHOWERS OR FLURRIES MAY PERSIST NEAR THE WESTERN  
FRINGE OF THE FORECAST AREA, NEAR THE SOUTHERN HERKIMER COUNTY  
IN THE WESTERN MOHAWK VALLEY. ANY SNOW ACCUMULATION WOULD BE  
VERY LIGHT. THE LOWERING SUBSIDENCE INVERSION SHOULD END THE  
ACTIVITY BY THE AFTERNOON, AS IT WILL BE PARTLY TO MOSTLY SUNNY  
AND COLD AS HIGHS WILL BE IN THE TEENS TO LOWER 20S OVER THE  
MTNS, AND MAINLY 20S IN THE VALLEYS THOUGH A FEW LOWER 30S ARE  
POSSIBLE OVER THE MID HUDSON VALLEY. TUE NIGHT, IDEAL  
RADIATIONAL COOLING MAY OCCUR WITH CLEAR/MOSTLY CLEAR SKIES,  
LIGHT TO CALM WINDS, AND FRESH SNOW COVER WITH THE SFC RIDGE  
BUILDING IN. LOWS MAY FALL TO ZERO TO 5 BELOW OVER THE SOUTHERN  
ADIRONDACKS, AND SOUTHERN GREENS, SINGLE DIGITS OVER THE REST OF  
THE FORECAST AREA, EXCEPT THE MID HUDSON VALLEY, SOUTHERN  
TACONICS, AND NW CT WHERE SOME LOWER TEENS ARE POSSIBLE.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SUNDAY/
 
 
THIS PERIOD WILL BE FRONT AND BACK-LOADED WITH WINTRY CONDITIONS,  
WITH A PERIOD OF DRY WEATHER IN BETWEEN. WEDNESDAY WILL START  
OFF CHILLY, AS HIGH PRESSURE GIVES WAY TO A LOW PRESSURE COMPLEX  
FROM THE DEEP SOUTH. THIS SYSTEM WORKS ITS WAY RAPIDLY UP INTO  
THE NORTHEAST, QUICKLY SPREADING CLOUDINESS ACROSS THE REGION ON  
WEDNESDAY, WITH SNOW LIKELY BY WEDNESDAY EVENING. THE EXACT  
EVOLUTION OF THIS SYSTEM WILL DECIDE HOW MUCH SNOW OUR FORECAST  
AREA GETS, AND WHETHER IT WILL END AS RAIN SHOWERS ON THURSDAY.  
FOR THE PAST 48 HOURS, THE GFS HAS BEEN FAIRLY CONSISTENT, AND  
HIGHS ON THURSDAY SHOULD REACH WELL INTO THE 40S FROM THE LAKE  
GEORGE- SARATOGA REGION ON SOUTH. RIGHT NOW, 2 TO 4 INCHES OF  
TOTAL SNOW LOOKS TO BE WHAT WE CAN EXPECT OUT OF THIS SYSTEM  
BEFORE ANY DAYTIME CHANGEOVER TO SHOWERS ON THURSDAY.  
 
THINGS DRY OUT AND SKIES BRIGHTEN TO END THE WORK WEEK, BUT  
TEMPERATURES SHOULD BE DECENT, WITH HIGHS RUNNING FROM AROUND 30  
DEGREES IN THE NORTHERN HIGH PEAKS...TO THE MID 40S ACROSS THE  
MID- HUDSON VALLEY. THE WEEKEND WILL BE EVEN WARMER AS THE NEXT  
SYSTEM ALSO LIFTS OUT OF THE DEEP SOUTH. SNOW OR MIXED  
PRECIPITATION OVERSPREADS OUR ENTIRE AREA SATURDAY NIGHT, WITH  
MOST LOCATIONS GOING OVER TO RAIN ON SUNDAY.  
 

 
   
AVIATION /03Z MONDAY THROUGH FRIDAY/
 
 
LOW PRESSURE WILL APPROACH FROM THE OHIO VALLEY TONIGHT BRINGING  
SNOW TO THE EASTERN NEW YORK AND WESTERN NEW ENGLAND TERMINALS.  
THE STORM SYSTEM WILL REDEVELOP EAST OF NEW JERSEY AND PASS  
SOUTH OF LONG ISLAND TOMORROW MORNING INTO THE AFTERNOON  
BRINGING A LIGHT TO MODERATE SNOWFALL.  
 
SNOW WILL GENERALLY DEVELOP FROM SOUTHWEST TO NORTHEAST ACROSS  
THE REGION TONIGHT, FIRST AT KPOU AROUND 02Z-03Z, KALB/KPSF  
AROUND 03Z-04Z, AND KGFL BY AROUND 07Z-08Z. THE SNOW WILL RESULT  
IN CONDITIONS DETERIORATING TO IFR, WITH VSBY LOWERING MORE  
QUICKLY THAN CIGS OVERNIGHT. WIDESPREAD IFR CONDITIONS ARE  
EXPECTED THROUGH THE MORNING HOURS, WITH SNOW PERSISTING. AS ICE  
NUCLEI IS LOST IN THE CLOUDS FOR A TIME MONDAY MORNING, SOME  
INTERMITTENT FREEZING DRIZZLE WILL BE POSSIBLE AT KPOU.  
CONDITIONS WILL GRADUALLY IMPROVE TO MVFR DURING THE AFTERNOON  
TO EARLY EVENING HOURS MONDAY.  
 
WINDS WILL INITIALLY BE NORTHEAST AROUND 5 KT OR LESS, BECOMING  
NORTHWEST AND INCREASING TO 10-12 KT WITH GUSTS NEAR 20 KT BY  
LATER MONDAY AFTERNOON.  
 
OUTLOOK...  
 
MONDAY NIGHT: LOW OPERATIONAL IMPACT. BREEZY NO SIG WX.  
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
WEDNESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.  
WEDNESDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SN...SLEET.  
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.  
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX  
 

 
   
HYDROLOGY
 
 
A STORM SYSTEM WILL BRING ACCUMULATING LIGHT TO MODERATE SNOWFALL  
TONIGHT INTO TOMORROW WITH TOTAL LIQUID EQUIVALENTS OF TWO TO  
FOUR TENTHS OF AN INCH.  
 
ANOTHER SEASONABLY COLD AND DRY STRETCH IS LIKELY MONDAY NIGHT  
THROUGH MOST OF THE DAY WEDNESDAY. SOME THICKENING OF ICE IS  
POSSIBLE ON THE MAIN STEM RIVERS, LAKES AND STREAMS.  
 
ANOTHER STORM SYSTEM IS EXPECTED LATE WEDNESDAY INTO THURSDAY  
AND THIS STORM WILL BRING SNOW CHANGING TO A WINTRY MIX AND/OR  
RAIN TO THE REGION. AS OF RIGHT NOW, ABOUT A QUARTER TO HALF  
INCH OF LIQUID EQUIVALENT IS EXPECTED.  
 
DRIER WEATHER LOOKS TO RETURN LATE IN THE WEEK INTO NEXT WEEKEND  
WITH SLIGHTLY ABOVE NORMAL TEMPS, BUT OVERNIGHT LOWS SHOULD  
FALL BELOW FREEZING WITH ANY SNOW MELT REFREEZING. NO  
SIGNIFICANT WARM-UPS OR HEAVY PRECIPITATION EVENTS ARE EXPECTED  
INTO NEXT WEEKEND.  
 
AS A RESULT, RIVER AND STREAM LEVELS WILL GENERALLY HOLD STEADY  
THROUGH AT LEAST THE END OF NEXT WEEK AND WIDESPREAD SNOW MELT,  
ICE MOVEMENT OR FLOODING IS NOT EXPECTED 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...WINTER WEATHER ADVISORY UNTIL 4 PM EST MONDAY FOR CTZ001-013.  
NY...WINTER WEATHER ADVISORY UNTIL 4 PM EST MONDAY FOR NYZ038>040-  
047>054-058>061-063>066-082.  
MA...WINTER WEATHER ADVISORY UNTIL 4 PM EST MONDAY FOR MAZ001-025.  
VT...NONE.  
 

 
 

 
SYNOPSIS...WASULA  
NEAR TERM...JPV/WASULA  
SHORT TERM...WASULA  
LONG TERM...ELH  
AVIATION...JPV  
HYDROLOGY...FRUGIS/WASULA  
 
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