January 18, 2015 Forecast Discussion

000
FXUS61 KALY 182055
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
355 PM EST SUN JAN 18 2015

.SYNOPSIS…
SURFACE LOW PRESSURE WILL DEVELOP IN THE MID ATLANTIC STATES AND
RACE UP THE COAST LATE TONIGHT…DEEPENING RAPIDLY AS IT MOVES
INTO THE GULF OF MAINE BY MONDAY. HIGH PRESSURE WILL SLOWLY BUILD
INTO THE REGION INTO MIDWEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/…
…FREEZING RAIN ADVISORY EXTENDED INTO THIS EVENING IN NORTHERN
SARATOGA…LAKE GEORGE REGION…MID HUDSON VALLEY AND SOUTHERN
VT…

ALL DAY…OBSERVED WEATHER ACROSS THE REGION HIGHLIGHTS ONE OF
THE MOST STRIKING EXAMPLES OF LOCAL EFFECTS AND HUGE DIFFERENCES
IN TEMPERATURES IN SHORT DISTANCES…THE POWER OF LOCAL EFFECTS
AND TERRAIN ON OBSERVED SENSIBLE WEATHER IN SHORT DISTANCES.

FREEZING RAIN IS TRANSITIONING TO RAIN IN PARTS OF THE EASTERN
CATSKILLS…MID HUDSON VALLEY…SOUTHERN VT…EAST OF THE GREEN
MOUNTAINS…AND THE LAKE GEORGE SARATOGA REGION. TEMPERATURES ARE
GENERALLY NEAR OR JUST ABOVE FREEZING IN THE ADVISORY AREA…WHILE
TEMPERATURES ARE IN THE UPPER 30S TO LOWER 40S IN MANY OTHER
AREAS. FROZEN GROUND AND DIABATIC COOLING STILL ANCHORING THE THE
COLD DENSE SURFACE COLD LAYER IN AREAS WHERE ADVISORIES CONTINUE.
WINDS ARE SOUTH IN THE CAPITAL DISTRICT TO EASTERN VT AND THE
BERKSHIRES…YET CALM TO LIGHT NORTH IN THE MID HUDSON VALLEY TO
NW CT AND CENTRAL MASSACHUSETTS. COLD FROZEN GROUND COULD STILL
ALLOW FOR ADDITIONAL LIGHT ACCUMULATIONS OF ICE ON EXPOSED
OBJECTS THROUGH AROUND 7 PM…SO ADVISORIES EXTENDED.

THE WESTERN EDGE OF THE STEADIER PRECIPITATION IS ALONG AND EAST
OF THE SCHOHARIE VALLEY AND CAPITAL DISTRICT AND LAKE GEORGE
SARATOGA REGION…WHICH IS WHY AREAS BELOW FREEZING FROM JOHNSTOWN
AND POINTS WEST ARE NOT INCLUDED IN THE FREEZING RAIN ADVISORY.
GUIDANCE SUGGESTS PRECIPITATION DEVELOPING IN WESTERN AREAS AND
MERGING WITH THE CURRENT AREA OF PRECIPITATION THROUGH THE
EVENING…AS BOUNDARY LAYER FRONTOGENESIS INCREASES A LONG WITH
UPPER DYNAMICS ASSOCIATED WITH THE UPPER SYSTEM GOING NEGATIVE
TILT. SO…INDICATING CHANCES FOR FREEZING RAIN IN THE CENTRAL
MOHAWK VALLEY WITH SOME SLEET UNTIL THE PRECIPITATION CHANGES TO
SNOW THROUGH THE EVENING. ANY FREEZING RAIN IN THE CENTRAL MOHAWK
VALLEY WILL BE HANDLED BY SPECIAL WEATHER STATEMENTS UNTIL THE
CHANGE TO SNOW.

HEAVY RAIN IN WESTERN NEW ENGLAND AND THE MID HUDSON VALLEY COULD
LEAD TO SOME NUISANCE URBAN AND SMALL STREAM FLOODING DEPENDING ON
HOW MUCH SNOW AND ICE BLOCK STORM DRAINS.

ONCE THE PRECIPITATION CHANGES TO SNOW IN OUR REGION THROUGH THIS
EVENING…JUST LIGHT ACCUMULATIONS IN THE REGION…WITH MAYBE UP
TO 3 OR 4 INCHES IN THE PEAKS OF THE SOUTHERN GREEN MOUNTAINS AND
AN COUPLE OF INCHES IN THE LAKE GEORGE AND NORTHERN SARTOGA
REGION. WEST TO NORTHWEST WINDS WILL INCREASE AND CLOUDS WILL HOLD
OVER THE REGION WITH LOWS ACROSS THE REGION IN THE UPPER 20S TO
LOWER 30S.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/…
GENERAL UPPER CYCLONIC FLOW ACROSS THE REGION…WITH PERIODS OF
LAKE EFFECT CLOUDS AND SNOW SHOWER ACTIVITY. A REINFORCING SHOT OF
COLDER AIR MONDAY COULD SUPPORT SOME SCATTERED TO ISOLATED SNOW
SHOWER ACTIVITY OVER MUCH OF THE AREA. SOME WINDY CONDITIONS SHOULD
HELP WITH MIXING MONDAY…EVEN WITH MORE CLOUDS THAN SUN…WITH
HIGHS WELL INTO THE 30S TO AROUND 40. WINDS WILL SLOWLY DIMINISH
MONDAY NIGHT THROUGH TUESDAY. WEST TO NORTHWEST FLOW OFF GREAT
LAKES ALONG WITH REINFORCING SHOT OF COLDER AIR SHOULD RESULT IN
MORE PERIODS OF CLOUDS…AND SOME SNOW SHOWER ACTIVITY INTO
WESTERN AREAS. HIGHS TUESDAY IN THE UPPER 20S TO MID 30S…COLDER
IN THE SOUTHERN ADIRONDACKS.

A CLIPPER LIKE NORTHERN STREAM UPPER IMPULSE IS EXPECTED TO TRACK
SOUTH AND EAST OF OUR REGION TUESDAY NIGHT AND WEDNESDAY…BUT
ACKNOWLEDGING THICKER CLOUDS AND ISOLATED TO SCATTERED SNOW
SHOWERS IN SOUTHERN AREAS. HIGHS WEDNESDAY IN THE UPPER 20S TO MID
30S…COLDER IN NORTHERN AREAS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/…
WEAK DISTURBANCES EMBEDDED WITHIN THE GENERAL NORTHWEST FLOW PATTERN
ACROSS THE EASTERN UNITED STATES WILL BE THE PREVAILING WEATHER
PATTERN FOR WEDNESDAY THROUGH SATURDAY.

EARLIER MODEL RUNS HAD THE FIRST WEAK WAVE MOVING JUST TO THE SOUTH
OF THE ALBANY FORECAST AREA ON WEDNESDAY…BRINGING SOME LIGHT
SNOW/SNOW SHOWERS TO MOST OF THE REGION. HOWEVER…THE 00Z GFS HAS
THE SYSTEM FURTHER SOUTH…WITH ONLY THE SOUTHERN PART OF THE REGION
FORECAST TO GET ANY SNOW. THE ECMWF IS EVEN FURTHER SOUTH WITH THIS
SYSTEM AND NO SNOW IS FORECAST FOR THE ENTIRE REGION. IN FACT…THE
ECMWF IS IMPLYING MAINLY SUNNY SKIES FOR WEDNESDAY. FOR NOW WILL
FORECAST PARTLY TO MOSTLY CLOUDY WITH A 20 TO 30 PERCENT CHANCE OF
SNOW SHOWERS ACROSS THE ALBANY FORECAST AREA…WITH THE HIGHEST POPS
SOUTH. HIGHS WEDNESDAY WILL BE IN THE 20S TO LOWER 30S.

WEAK HIGH PRESSURE WILL BRING FAIR AND DRY WEATHER TO THE REGION
WEDNESDAY NIGHT AND THURSDAY. LOWS WEDNESDAY NIGHT WILL RANGE FROM
AROUND ZERO OVER THE ADIRONDACKS…TO THE MID TEENS SOUTHEAST. HIGHS
THURSDAY WILL BE IN THE UPPER TEENS AND 20S.

A COUPLE OF WEAK SHORT WAVE TROFS MAY BRING SOME SCT SNOW SHOWERS TO
THE REGION THURSDAY NIGHT INTO FRIDAY…WITH A MORE SIGNIFICANT TROF
BRINGING A BETTER CHANCE FOR LIGHT SNOW OR SNOW SHOWERS TO THE
REGION ON SATURDAY. EVEN WITH THESE WAVES MOVING THROUGH…THE
AIRMASS OVER THE REGION WILL REMAIN DRY…SO HAVE ONLY FORECAST
SLIGHT OR LOW CHANCE POPS ACROSS THE HIGHER TERRAIN AREAS OF NY AND
VT…AND ALSO ACROSS THE MOHAWK VALLEY. THE REST OF THE AREA IS
FORECAST TO REMAIN MAINLY DRY…OR HAVE ONLY FORECAST A SLIGHT
CHANCE OF SNOW SHOWERS.

LOWS THURSDAY AND FRIDAY NIGHTS WILL BE IN THE SINGLE NUMBERS TO MID
TEENS. HIGHS FRIDAY AND SATURDAY IN THE UPPER TEENS AND 20S.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/…
THE TAF PERIOD KICKS OFF WITH IFR CONDITIONS. TEMPERATURES HAVE
WARMED ABOVE FREEZING AT ALL BUT KGFL WHICH STARTED THE MORNING OFF
IN THE SINGLE DIGITS. STILL…EXPECTING KGFL PRECIP TO ONSET AS
-FZRA…BUT PLENTY OF MILDER SURFACE AIR SOUTH AND WEST SHOULD TURN
THINGS OVER TO LIQUID RATHER QUICKLY…SAY BY 20Z. THE COLD FRONT
ASSOCIATED WITH THIS SYSTEM WILL DRIVE THINGS OUT OVERNIGHT…SO
THAT BY 12Z ALL AIRPORTS ARE AT VFR WITH NO FURTHER PRECIPITATION.
HOWEVER…OVERCAST IN THE LOWER VFR RANGE WILL PERSIST…WITH
WRAPAROUND FLOW ACROSS THE GREAT LAKES…AND NO SIGNIFICANT HIGH
PRESSURE TO PROVIDE SUBSIDENCE.

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: NO OPERATIONAL IMPACT. ISOLATED SHSN.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.

&&

.HYDROLOGY…
IT NOW APPEARS THAT OUR WESTERN NEW ENGLAND PORTION OF OUR
HYDROLOGIC SERVICE AREA (HSA) WILL RECEIVE TOTALS OF 1 TO 2
INCHES OF RAIN THROUGH THIS EVENING. THE GROUND IS FROZEN AND THERE
IS SOME ICE ON THE RIVERS. THE GOOD NEWS…SNOWFALL IS BELOW
AVERAGE AND TEMPERATURE SHOULD NOT GET ALL THAT WARM (TO MELT THE
EXISTING SNOW PACK).

THE GEFS/NAEFS AND SREF DO NOT FORECAST ANY OF OUR RIVER POINTS TO
FLOOD…BUT SEVERAL POINTS ON THE HOUSATONIC COULD REACH ACTION
STAGE LATER TONIGHT. RAIN MIGHT FALL HARD ENOUGH TO PRODUCE
PONDING OF WATER IN AREAS OF POOR DRAINAGE THIS EVENING.

THE RAIN WILL END AS A RAIN SNOW MIX OR JUST SNOW…WITH ONLY MINOR
ACCUMULATIONS EXPECTED. IT WILL TURN SOMEWHAT COLDER ON MONDAY WHICH
WOULD ALLOW THE RUNOFF TO SLOWDOWN. THEN IT TURNS EVEN COLDER MONDAY
NIGHT THROUGH MUCH OF THE UPCOMING WEEK WITH MAINLY DRY CONDITIONS.
THE COLD WEATHER COULD ALLOW FOR SOME ADDITIONAL ICE TO DEVELOP ON
OUR RIVERS.

THE REMAINDER OF THE HSA FROM THE HUDSON VALLEY WEST WILL RECEIVE AN
INCH OR LESS OF RAINFALL WITH FEW IF ANY HYDROLOGIC ISSUES…BUT
EVEN HERE THERE COULD SOME MINOR PONDING ISSUES.

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…FREEZING RAIN ADVISORY UNTIL 7 PM EST THIS EVENING FOR
NYZ041>043-063>066-083-084.
MA…NONE.
VT…FREEZING RAIN ADVISORY UNTIL 7 PM EST THIS EVENING FOR VTZ014-
015.

&&

$$
SYNOPSIS…NAS
NEAR TERM…NAS
SHORT TERM…NAS
LONG TERM…KL
AVIATION…ELH
HYDROLOGY…HWJIV/NAS

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