January 16, 2014 Forecast Discussion

000
FXUS61 KALY 161155
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
655 AM EST THU JAN 16 2014

.SYNOPSIS…
STEADY PRECIPITATION…MAINLY IN THE FORM OF SNOW…WILL CONTINUE
THIS MORNING AND INTO THE AFTERNOON…AS SOUTHERLY FLOW ALOFT
CONTINUES TO TRANSPORT MOISTURE INTO OUR REGION NORTH OF A COLD
FRONT THAT HAS SHIFTED SOUTH AND EAST INTO NEW ENGLAND. WEAK HIGH
PRESSURE WILL BUILD IN LATE TODAY AND TONIGHT…WITH DRY
CONDITIONS RETURNING. SEVERAL TROUGHS OF LOW PRESSURE WILL THEN
MOVE ACROSS THE REGION FROM LATE FRIDAY THROUGH THE
WEEKEND…BRINGING A PERIODIC THREAT FOR SNOW SHOWERS.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 655 AM EST…SNOW CONTINUES TO RE-GENERATE ACROSS GENERALLY
THE SAME AREAS AS EARLIER THIS MORNING…MAINLY FROM THE CAPITAL
DISTRICT WESTWARD INTO THE EASTERN MOHAWK VALLEY AND EASTERN
CATSKILLS. EXPANDED HIGHER POPS FARTHER WEST WITH THIS UPDATE…AS
PRECIP FROM KBGM RADAR HAS INCREASED UPSTREAM AND IT HEADED FOR
THE MOHAWK VALLEY AND SOUTHEAST ADIRONDACKS TOO. INCREASE TOTAL
ACCUMULATIONS FOR AREAS WHERE SNOW HAS BEEN MOST PERSISTENT AND
WHERE ADDITIONAL SNOW IS LIKELY. EXPECTING GENERALLY 1-2 INCHES
EXCEPT 2-4 FOR PORTIONS OF THE EASTERN MOHAWK VALLEY AND
HELDERBERGS NORTHWARD TO THE SARATOGA REGION WHERE SOME 2 INCHES
REPORTS HAVE ALREADY COME IN.

THIS AREA OF SNOW CONTINUES TO NOT BE DEPICTED WELL BY ANY OF OUR
MODEL GUIDANCE…INCLUDING HIRES MODELS MAKING FOR A DIFFICULT
FORECAST. WE BELIEVE THE PRECIP IS BEING PRODUCED BY MOISTURE
SURGING NORTHWARD INTO THE AREA DUE TO SOUTHERLY FLOW
ALOFT…BEING TRANSPORTED OVER THE LOW LEVEL FRONTAL BOUNDARY
LOCATED IN NEW ENGLAND…CAUSING ENHANCED LIFT DUE TO OVER-
RUNNING. SNOW IS FALLING TO THE NORTH AND WEST OF THE FRONT IN OUR
AREA.

SINCE THE FLOW PATTERN ONLY GRADUALLY CHANGES THROUGH TODAY…
PRECIP SHOULD CONTINUE THROUGH AT LEAST THE MORNING…AND LIKELY
INTO THE AFTERNOON FOR EASTERN AREAS…AS THE FRONTAL BOUNDARY
SLOWLY SHIFTS FARTHER EAST. THE UPPER LEVEL FLOW WILL REMAIN
SOUTHERLY AS THE SURFACE BOUNDARY CREEPS EASTWARD ACROSS NEW
ENGLAND. WESTERN NEW ENGLAND WILL BE LAST AREA TO SEE PRECIP
TAPER OFF BY EARLY EVENING. THIS PESKY SYSTEM FINALLY SHOULD EXIT
THE EASTER PART OF THE AREA 6-8 PM.

TEMPERATURES WILL SLOWLY RISE TO MAX READING OF THE MID TO UPPER 30S
FOR MOST VALLEY LOCATIONS…BUT NOT UNTIL LATE AFTERNOON WHEN SOME
PEAKS OF SUN ARE POSSIBLE. THE HIGHER TERRAIN WILL BE COOLER WITH
GENERALLY UPPER 20S TO LOWER 30S EXPECTED.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/…
TRANQUIL CONDITIONS ARE EXPECTED TONIGHT…AS WE WILL BE BETWEEN
WEATHER SYSTEMS. RIDGING AT THE SURFACE WILL PROVIDE SUBSIDENCE AND
DRY CONDITIONS. CLOUDS WILL TEND TO INCREASE TOWARDS MORNING AHEAD
OF THE NEXT SYSTEM…AS A LARGE AMPLITUDE UPPER LEVEL TROUGH
APPROACHES FROM THE GREAT LAKES AND OHIO VALLEY REGION. TEMPS STILL
LOOK TO BE ABOVE NORMAL…ESPECIALLY WITH THE INCREASING CLOUDS LATE.

ON FRIDAY…THE AFOREMENTIONED UPPER TROUGH IS FORECAST TO DEEPEN
FURTHER TO OUR WEST…WHILE A SOUTHWEST FLOW ALOFT REMAINS OVER OUR
REGION. WITH NOT MUCH IN THE WAY OF FORCING SEEN IN MODEL
GUIDANCE…EXPECTING MAINLY DRY CONDITIONS EXCEPT FOR SLIGHT CHANCE
TO CHANCE POPS MAINLY NORTH AND WEST OF THE CAPITAL REGION
ASSOCIATED WITH CONVERGENCE ALONG A WEAK SURFACE TROUGH. SIMILAR
CONDITIONS ARE EXPECTED FRIDAY EVENING AND INTO THE OVERNIGHT…AS
THE TROUGH SLOWLY MOVES EASTWARD ACROSS THE AREA.

LATE FRIDAY NIGHT INTO SATURDAY THERE APPEARS TO BE A BETTER CHANCE
FOR SOME LIGHT ACCUMULATING SNOW FOR A PORTION OF THE AREA…AS A
STRONGER SHORT WAVE TROUGH AND VORT MAX SWING THROUGH THE REGION
FROM WEST TO EAST. THERE ARE SOME SUBTLE MODEL DIFFERENCES IN TERMS
OF AMOUNTS/AREAS OF QPF DUE TO COMPLEX SMALL SCALE FEATURES
PRODUCING ASCENT. SINCE THIS POSSIBLE MINOR EVENT IS STILL A FEW
DAYS OUT…WILL ONLY MENTION CHANCE POPS AT THIS TIME UNTIL THINGS
CAN BE REFINED. TEMPERATURES COULD BRIEFLY WARM INTO THE MID TO
PERHAPS UPPER 30S IN VALLEY LOCATIONS…HOWEVER DUE TO STEEP LAPSE
RATES ONCE PRECIP STARTS RAPID SURFACE COOLING WILL OCCUR AND WILL
BE IN FORM OF SNOW.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/…
RAPIDLY MOVING CLIPPERS AND GRADUALLY TURNING COLDER EARLY DURING
THE LONG TERM PERIOD…THEN THE GFS/ECMWF BOTH AGREE THAT BY
WEDNESDAY AND THURSDAY OF NEXT WEEK ANOTHER MASSIVE OUTBREAK OF
ARCTIC AIR WILL SURGE INTO THE REGION WITH 850 MB TEMPS FORECAST TO
DROP TO AROUND 25 DEG CELSIUS BELOW ZERO ACROSS THE FORECAST
AREA…WITH 30 DEGREES CELSIUS BELOW ZERO JUST TO THE NORTH OF THE
FORECAST AREA.

THE RAPID MOVEMENT AND FLUCTUATIONS FROM RUN TO RUN MAKES TIMING THE
MOVEMENT OF ANY SHORT WAVE TROF AND ASSOCIATED PCPN VERY DIFFICULT.
IN ADDITION…MOST OF THESE SYSTEM APPEAR TO BE STARVED FOR
MOISTURE…SO MOST OF THE TIME POPS OF ONLY 20 TO 40 PERCENT ARE
FORECAST. THE BEST CHANCE FOR ANY WIDESPREAD SNOW APPEARS TO BE
TUESDAY INTO TUESDAY NIGHT AS A COASTAL SYSTEM TRIES TO FORM WHEN A
SHORT WAVE TROF MOVES OFF THE COAST. AT THIS TIME IT APPEARS ANY
STRONG DEVELOPMENT WILL OCCUR TO FAR TO OUR EAST FOR SIGNIFICANT
SNOW HERE…SO ONLY POPS OF 20 TO 40 PERCENT WILL BE FORECAST FOR
THIS SYSTEM AS WELL.

TEMPERATURE WISE…LOWS SATURDAY AND SUNDAY NIGHTS WILL BE IN THE
TEENS AND LOWER 20S. HIGHS SUNDAY AND MONDAY IN THE MID 20S TO MID
30S. LOWS MONDAY NIGHT IN THE UPPER SINGLE DIGITS AND TEENS. HIGHS
TUESDAY IN THE UPPER TEENS TO AROUND 30. THE ARCTIC AIR WILL BEGIN
TO BE FELT TUESDAY NIGHT WITH LOWS JUST BELOW ZERO IN THE
ADIRONDACKS…AND THE SINGLE NUMBERS TO MID TEENS ELSEWHERE. ON
WEDNESDAY AND THURSDAY HIGHS WILL GENERALLY BE IN THE SINGLE NUMBERS
AND TEENS. LOWS WEDNESDAY NIGHT WILL RANGE FROM 10 BELOW ZERO TO
AROUND 7 ABOVE. DURING THE PERIOD FROM WEDNESDAY THROUGH THURSDAY…
THERE WILL ALSO BE A GUSTY NORTHWEST WIND…SO WIND CHILL VALUES
WILL BE MUCH COLDER.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/…
THE AREA OF SNOW AFFECTING THE REGION…ESPECIALLY THE KGFL/KALB TAF
SITES…HAS BEEN HANDLED POORLY BY THE MODELS…AND THE LATEST SET
OF TAFS WILL BE FORECAST BASED ON RADAR TRENDS. EXPECT THE SNOW WITH
MVFR/IFR CONDITIONS TO CONTINUE AT THE KALB/KGFL TAF SITES UNTIL
AROUND 15Z/16Z. AT THIS TIME IT APPEARS THAT THE NARROW BAND OF SNOW
SHOULD REMAIN TO THE WEST OF THE KPOU/KPSF TAF SINCE IT CURRENTLY
SHOWS LITTLE SIGH OF ANY EASTWARD MOVEMENT. HAVE NOT FORECAST ANY
IFR CONDITIONS AT KPOU…ONLY THE POTENTIAL FOR MVFR CIGS/VSBYS. AT
KPSF…CIGS HAVE ALREADY BEEN IFR AT TIMES…SO WILL FORECAST
MVFR/IFR CONDITIONS THERE THROUGH 16Z.

AFTER ABOUT 16Z EXPECT VFR CIGS AT THE TAF SITES THROUGH THE REST OF
THE TAF PERIOD WHICH ENDS AT 12Z FRIDAY.

WINDS WILL BE MAINLY NORTH TO NORTHWEST AT LESS THAN 10 KTS AT THE
TAF SITES THROUGH LATE AFTERNOON…THEN BECOME CALM OR LIGHT AND
VARIABLE.

OUTLOOK…

FRIDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN.
SUNDAY NIGHT TO MARTIN LUTHER KING JR DAY: LOW OPERATIONAL IMPACT.
SLIGHT CHANCE OF SHSN.

&&

.HYDROLOGY…
NO HYDRO PROBLEMS ARE EXPECTED THROUGH THE NEXT FIVE DAYS.

RIVER AND STREAM LEVELS ARE CURRENTLY ELEVATED…BUT WITHIN
BANKS…DUE TO THE RECENT RAINFALL AND SNOW MELT. THROUGH THE
WEEKEND…LITTLE PRECIPITATION IS EXPECTED ACROSS THE REGION. MOST
OF THE LITTLE PRECIP THAT WILL OCCUR WILL MAINLY BE IN THE FORM OF
LIGHT SNOW SHOWERS…WHICH WOULD HAVE LITTLE EFFECT ON AREA RIVERS
AND STREAMS. AS A RESULT…STREAM FLOWS SHOULD GRADUALLY LOWER OVER
THE NEXT FEW DAYS. WITH SOMEWHAT COLD TEMPERATURES RETURNING OVER
THE WEEKEND…RIVER AND LAKE ICE WILL BEGIN TO REFORM AND
STRENGTHEN. SUBSTANTIALLY COLDER AIR MAY MOVE IN TOWARDS THE MIDDLE
OF NEXT WEEK…WHICH WOULD RESULT IN MORE ICE FORMATION.

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…NAS
AVIATION…GJM
HYDROLOGY…FRUGIS/JPV

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