Area Forecast Discussion
Issued by NWS Buffalo, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
000
FXUS61 KBUF 151753
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1253 PM EST MON DEC 15 2014

.SYNOPSIS...
CLOUDY CONDITIONS WILL CONTINUE FOR THE REMAINDER OF THE DAY. TEMPERATURES
WILL REMAIN NEARLY STEADY OVERNIGHT AND RISE SLIGHTLY ON
TUESDAY AS A LOW PRESSURE SYSTEM BRINGS RAIN SHOWERS. THESE WILL
TRANSITION TO SNOW SHOWERS BY WEDNESDAY INTO THURSDAY AS COLDER
AIR ARRIVES FOR THE SECOND HALF OF THE WEEK.

&&

.NEAR TERM /THROUGH TUESDAY/...
THE RIDGE OVER THE NORTHEAST US TOGETHER WITH HIGH PRESSURE AT THE
SURFACE HELPING PROVIDE LARGE SCALE SUBSIDENCE AND HENCE A STRONG
CAP OVER THE REGION...TYPICAL FOR THIS TIME OF YEAR. MOISTURE
TRAPPED BELOW THE INVERSION CANNOT EFFECTIVELY MIX OUT. THE RESULT
IS CONTINUED STRATUS WITH PATCHY DRIZZLE...AND FOG OVER THE HIGHER
TERRAIN. THIS IS EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE
AFTERNOON. THERE IS CLEAR SKIES MOST OF OH WITH A HIGHER INVERSION
UPSTREAM...BUT THIS MAY HAVE TROUBLE RELEASING THE TRAPPED
MOISTURE OVER THE HIGHER ELEVATIONS OF WESTERN PA/NY. LATER
TONIGHT AND TUESDAY...A SYSTEM OVER MO WILL SLOWLY MOVE ACROSS
LOWER MI AND INTO SOUTHERN ONTARIO. A PERIOD OF WARM AIR ADVECTION
IS EXPECTED TO MOVE IN SOUTH OF THE LOW...WITH A 2-4 PERIOD OF RAIN
SPREADING ACROSS WESTERN NY AND INTO CENTRAL NY DURING TUESDAY.
THIS MAY BE FOLLOWED BY SCATTERED SHOWERS FOR THE REMAINDER OF THE
DAY. TEMPERATURES MAY HOVER NEAR FREEZING AT THE START...BUT
SHOULD INCREASE AS ANY RAIN MOVES IN. WILL CONTINUE TO KEEP THE
FORECAST ALL LIQUID...ALTHOUGH THERE IS A LOW CHANCE FOR AN
INITIAL BRIEF MIX EAST OF THE GENESEE VALLEY. QPF SHOULD RANGE
FROM ABOUT .1 TO .25 FOR THROUGH TUESDAY AFTERNOON.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
BEHIND THE FIRST WAVE OF SHOWERS THERE WILL STILL BE ENOUGH WEAK
ASCENT AND CONVERGENCE WITHIN THE TROUGH TO KEEP A HIGH LIKELIHOOD
OF A FEW SHOWERS ACROSS WESTERN NY TUESDAY EVENING...BUT QPF WILL
BE LIGHT. WITH SATURATED LOW LEVELS SOME FOG IS EXPECTED ACROSS
THE HIGHER TERRAIN TUESDAY NIGHT AS LOW CLOUDS INTERSECT THE
HILLS.

EAST OF LAKE ONTARIO SOMEWHAT STEADIER SHOWERS WILL LAST THROUGH
TUESDAY NIGHT AND EVEN INTO WEDNESDAY AS THE MID LEVEL TROUGH AND
SURFACE LOW ELONGATE IN AN EAST/WEST ORIENTATION ALLOWING STRONGER
ASCENT TO LINGER. PTYPE MAY BECOME A COMPLICATING FACTOR ACROSS THE
HIGHER TERRAIN EAST OF LAKE ONTARIO AS WELL. 850MB TEMPS ARE ONLY
NEAR 0C...BUT AN EXAMINATION OF MODEL POINT SOUNDINGS FROM BOTH THE
NAM AND GFS SHOW SOME POTENTIAL FOR THE BOUNDARY LAYER TO BECOME
ISOTHERMAL NEAR 0C...WHICH MAY ALLOW SOME WET SNOW TO MIX IN ACROSS
THE HIGHER TERRAIN OF THE TUG HILL AND WESTERN ADIRONDACKS...AND
EVEN SOME POTENTIAL FOR A CHANGE TO ALL WET SNOW. ACROSS LOWER
ELEVATIONS THE BOUNDARY LAYER SHOULD STAY WARM ENOUGH FOR ALL RAIN.

ON WEDNESDAY MODERATE COLD ADVECTION WILL SPREAD FROM WEST TO EAST
ACROSS THE AREA TO THE SOUTH OF LOW PRESSURE MOVING SLOWLY EAST
ALONG THE OTTAWA VALLEY. A DRY SLOT WILL PUSH INTO WESTERN NY DURING
THE DAY...SO EXPECT A GENERAL DECREASE IN PRECIP POTENTIAL. THE
AIRMASS MAY GROW JUST COLD ENOUGH TO SUPPORT A WEAK LAKE RESPONSE
ACROSS THE WESTERN SOUTHERN TIER...BUT INVERSION HEIGHTS AROUND 5K
FEET WILL KEEP THIS VERY LIMITED. EAST OF LAKE ONTARIO DEEPER
MOISTURE AND ASCENT REMAIN...WITH HIGHER CHANCES OF PRECIP THROUGH
THE DAY ESPECIALLY IN UPSLOPE AREAS EAST OF LAKE ONTARIO. PTYPE WILL
GRADUALLY TRANSITION FROM RAIN TO SNOW DURING THE COURSE OF THE DAY
FROM WEST TO EAST AND FROM HIGHER ELEVATIONS TO LOWER DURING THE DAY
AS THE BOUNDARY LAYER COOLS. ANY ACCUMULATION WILL BE LIMITED TO
HIGHER TERRAIN AND EVEN THERE SHOULD BE LIGHT.

WEDNESDAY NIGHT THE SAME BASIC PATTERN CONTINUES WITH DEEPER
MOISTURE AND ASCENT EAST OF LAKE ONTARIO. THIS WILL CONTINUE TO
SUPPORT SNOW SHOWERS...WITH UPSLOPE AND SOME LAKE ENHANCEMENT
POSSIBLY BRINGING LIGHT TO MODERATE ACCUMULATIONS TO THE TUG HILL
AND WESTERN FOOTHILLS OF THE ADIRONDACKS. A FEW LIGHT SNOW SHOWERS
MAY ALSO BE FOUND ACROSS THE WESTERN SOUTHERN TIER OFF LAKE ERIE...
BUT A MUCH DRIER SYNOPTIC SCALE AIRMASS AND LOW INVERSION WILL KEEP
THIS VERY LIMITED. OUTSIDE OF THESE TWO AREAS IT SHOULD BE MAINLY
DRY ALONG THE THRUWAY CORRIDOR FROM BUFFALO TO ROCHESTER.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
ON THURSDAY THE BOUNDARY LAYER FLOW WILL BECOME NORTHWEST IN THE
WAKE OF A DEEPENING LOW OVER NEW BRUNSWICK. THE AIRMASS WILL BE JUST
COLD ENOUGH TO SUPPORT A LIMITED LAKE RESPONSE WITH SNOW SHOWERS
LIKELY SOUTHEAST OF THE LAKES. THIS WEAK LAKE RESPONSE WILL CONTINUE
THROUGH THURSDAY NIGHT AND FRIDAY AS PERSISTENT NORTHWEST FLOW
CONTINUES WITH 850MB TEMPS AROUND -10C...PER THE FAVORED COLDER
ECMWF SOLUTION. EXPECT ANY ACCUMULATIONS TO BE VERY MINOR. HIGHS
BOTH DAYS WILL BE IN THE LOWER 30S ACROSS LOWER ELEVATIONS AND UPPER
20S ACROSS HIGHER TERRAIN...JUST A TOUCH BELOW AVERAGE FOR MID TO
LATE DECEMBER.

HIGH PRESSURE WILL BUILD INTO THE LOWER LAKES AND NEW ENGLAND FRIDAY
NIGHT AND BRING AN END TO THE WEAK NORTHWEST FLOW LAKE EFFECT. MODEL
GUIDANCE BEGINS TO DIVERGE OVER THE WEEKEND WITH THE HANDLING OF A
SOUTHERN STREAM CUTOFF LOW. THIS SYSTEM WILL REMAIN PROGRESSIVE AS
IT CROSSES THE TENNESSEE VALLEY EARLY SATURDAY BEFORE REACHING THE
EASTERN SEABOARD SATURDAY NIGHT AND SUNDAY. THE GFS REMAINS FASTER
AND MORE OPEN WITH THIS SYSTEM...TAKING A WAVE TO THE WEST OF THE
APPALACHIANS SATURDAY BEFORE ALLOWING SOME SECONDARY CYCLOGENESIS
WELL OFF THE MID ATLANTIC COAST. THE ECMWF IS STRONGER WITH A MAIN
FOCUS ON EAST COAST CYCLOGENESIS AND A STRONGER SUPPRESSING HIGH
PRESSURE OVER THE GREAT LAKES AND NORTHERN NEW ENGLAND. ALL OF THE
GEFS ENSEMBLE MEMBERS FOLLOW A SIMILAR SOLUTION TO THE OPERATIONAL
GFS.

GIVEN THE MODEL DIFFERENCES THE BEST COURSE OF ACTION WILL BE TO
STICK WITH CONTINUITY...AND LEAVE SATURDAY DRY THEN A LOW CHANCE OF
SNOW ON SUNDAY GIVEN THE LOOK OF SOME PREVIOUS MODEL RUNS. IT WILL
NOT BE OVERLY COLD OVER THE WEEKEND...BUT JUST COLD ENOUGH TO
SUPPORT SNOW AS A PRECIP TYPE IF THE SYSTEM MOVES CLOSE ENOUGH TO
PRODUCE ANY PRECIP ACROSS OUR REGION.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A LOW DECK OF STRATUS CLOUDS REMAINS ACROSS THE FORECAST
AREA...RESULTING MOSTLY IFR CONDITIONS. CURRENT CONDITIONS ARE
EXPECTED TO HOLD THROUGH MOST OF THE AFTERNOON WITH MEAGER
IMPROVEMENT TOWARD THIS EVENING AS DEVELOPING SOUTHEASTERLY WINDS HELP TO
SCATTER OUT THE CLOUD DECK. KART...WHICH IS CURRENTLY MVFR WILL
LIKELY REMAIN SO THROUGH THE TAF PERIOD.

THERE IS A SMALL WINDOW FOR TAF SITES TO POSSIBLY SEE VFR CONDITIONS
OVERNIGHT TONIGHT...HOWEVER CONFIDENCE IN THAT REMAINS LOW GIVEN THE
PERSISTENCE OF THE LOW-LEVEL MOISTURE/CLOUD DECK. KART PROBABLY HAS
THE BEST CHANCE OF SEEING VFR TONIGHT WHERE MOISTURE LOOKS MORE
SHALLOW. KJHW IS LEAST LIKELY TO SEE VFR CONDITIONS AS RAIN WILL
MOVE INTO THE SITE BY SUNRISE...KEEPING MVFR/IFR CONDITIONS IN
PLACE. RAIN WILL THEN SPREAD INTO OTHER TAF AREAS OVER WESTERN NY
BY 18Z.

OUTLOOK...
TUESDAY NIGHT...
WEDNESDAY AND THURSDAY...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.
FRIDAY AND SATURDAY...VFR.

&&

.MARINE...
QUIET CONDITIONS WILL PERSIST ON THE LAKES THROUGH TUESDAY...WITH
NEARLY CALM WINDS TODAY AND INCREASING SOUTHEASTERLY WINDS AND RAIN
SHOWERS ON TUESDAY. THE NEXT CHANCE FOR HIGHER WINDS AND WAVES
ACROSS THE LAKES WILL BE WEDNESDAY INTO THURSDAY AS A LOW PRESSURE
SYSTEM MOVES ACROSS THE GREAT LAKES.

&&

.CLIMATE...
A RELATIVELY MILD PATTERN WILL CONTINUE THROUGH THE NEXT 10 DAYS OR
SO WITH ONLY RELATIVELY BRIEF INTRUSIONS OF COLDER AIR MOST NOTABLY
LATER THIS WEEK. ONE MORE SOUTHERN STREAM SYSTEM WILL BEAR WATCHING
FOR A POSSIBLE NORTHEAST STORM NEXT WEEKEND.

THERE ARE GROWING SIGNS THAT THIS RELATIVELY MILD PATTERN WILL COME
TO AN END TOWARDS THE END OF THE MONTH. GEFS AND NAEFS ENSEMBLES
OVER THE PAST SEVERAL DAYS CONTINUE TO SUPPORT A TREND OF LOWERING
NAO INDEX AND THE DEVELOPMENT OF A STRONGER POSITIVE PNA TYPE
PATTERN WITH A BUILDING WEST COAST RIDGE FORCING DOWNSTREAM TROUGH
AMPLIFICATION ACROSS THE CENTRAL AND EASTERN CONUS. IT APPEARS THIS
PATTERN WILL HAVE SOME STAYING POWER...SO EXPECT A TREND TOWARDS
MORE PERSISTENT MID WINTER COLD BY THE END OF THE MONTH. IT APPEARS
THIS PATTERN CHANGE WILL BEGIN IN EARNEST SOMETIME AROUND CHRISTMAS
DAY...PLUS OR MINUS A FEW DAYS. THERE ARE SOME SIGNS IN GEFS
ENSEMBLE MEMBERS THAT THE START OF THE PATTERN CHANGE MAY BE USHERED
IN WITH A SIGNIFICANT SYSTEM SOMEWHERE IN THE EASTERN CONUS. STAY
TUNED.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...CHURCH/ZAFF
NEAR TERM...ZAFF
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...ZAFF
MARINE...CHURCH
CLIMATE...HITCHCOCK







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.