Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 040602
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
202 AM EDT SAT JUL 4 2015

.SYNOPSIS...
A WEAK SYSTEM WILL BRING SOME SHOWERS AND POSSIBLY A FEW THUNDERSTORMS
TO AREAS MAINLY SOUTHEAST OF BUFFALO...ROCHESTER... AND WATERTOWN
TODAY. THEN HIGH PRESSURE WILL REGAIN CONTROL WITH DRY WEATHER
THIS EVENING THROUGH MONDAY. THE NEXT WEATHER SYSTEM IS EXPECTED
TO ARRIVE TUESDAY OR TUESDAY NIGHT.

&&

.NEAR TERM /THROUGH TODAY/...
AT 200 AM...RADAR SHOWS A FAIRLY SOLID AREA OF LIGHT RAIN ACROSS
CENTRAL PENNSYLVANIA MOVING NORTHEAST. FOLLOWING ITS TRAJECTORY
IT WILL CLIP THE SE CWA BOUNDARY WITH RAIN LIKELY SOUTH OF A
WELLSVILLE TO SYRACUSE LINE.

A SIGNIFICANT PORTION OF HIGH RESOLUTION MODEL GUIDANCE FORECASTS
SHOWERS DEVELOP NORTH OF THIS AREA. SO FAR THERE IS NO EVIDENCE OF
THIS HAPPENING ON RADAR. ALSO...THE 00Z BUFFALO SOUNDING SHOWS DRY
AIR BENEATH 500MB. BASED ON THIS...THE FORECAST GOES
SIGNIFICANTLY BELOW MODEL CONSENSUS QPF IN FAVOR OF THE GENERALLY
DRIER HRRR/RGEM SOLUTIONS. FEEL THAT WITH TIME A FEW SHOWERS MAY
DEVELOP NORTH OF THIS AREA AS FORECAST BY GUIDANCE...BUT THAT
COVERAGE WILL BE SPARSE. OTHERWISE...MID AND HIGH CLOUDS FROM
THIS DISTURBANCE WILL HELP LIMIT RADIATIONAL COOLING TONIGHT.

FOR TODAY...ANY PRECIPITATION ASSOCIATED WITH THE WEAK SYSTEM
SHOULD QUICKLY MOVE OFF TO THE EAST DURING THE MORNING. BEHIND
THIS...THERE MAY BE ENOUGH INSTABILITY AND WEAK LIFT ALONG LAKE
BREEZE BOUNDARIES DURING THE AFTERNOON TO KICK OFF SCATTERED AND
THUNDERSTORMS INLAND FROM THE LAKES DURING THE AFTERNOON...WITH
THIS ACTIVITY TRACKING EASTWARD WITH TIME AND NOT TENDING TO LAST
TOO LONG AT ANY GIVEN LOCATION.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
PREVIOUS FORECAST IN GOOD SHAPE THIS EVENING WITH 18Z MODEL
GUIDANCE SHOWING SIMILAR TRENDS TO THE PREVIOUS 12Z GUIDANCE.
THERE REMAINS SOME UNCERTAINTY WITH REGARDS TO THE COLD FRONTAL
TIMING FOR THE TUESDAY WEDNESDAY TIME FRAME...SO FOR NOW CHANCE
POPS COVERING BOTH DAYS WILL REMAIN IN PLAY. PREVIOUS RELEVANT
THINKING FOLLOWS.

RIDGING ALOFT AND A DRIER AIRMASS MOVE INTO THE REGION FOR SUNDAY.
WITH NORTHWESTERLY FLOW BEHIND A COOL FRONT AND 850 MB TEMPERATURES
AROUND +12 TO +14C...EXPECT THAT FULL SUNSHINE AND MIXING UP TO
ABOUT 850 MB WILL RESULT IN HIGH TEMPERATURES IN THE UPPER 70S TO
LOW 80S. LIGHT MEAN FLOW UNDER THE SURFACE HIGH WILL ALLOW LAKE
BREEZES TO DOMINATE OFF BOTH LAKES ERIE AND LAKE ONTARIO...BUT
SHOULD MAKE FOR AN EXCELLENT RECREATION DAY AS PART OF THE HOLIDAY
WEEKEND.

BY MONDAY...SOUTHERLY FLOW INCREASES ACROSS THE FORECAST AREA IN
RESPONSE TO A WAVE TRACKING ACROSS THE UPPER GREAT LAKES AND
ATTENDANT SURFACE LOW INTO THE MIDWEST. INCREASED WARM ADVECTION AND
DOWNSLOPE / OFF SHORE FLOW WILL PUSH TEMPERATURES SOLIDLY INTO THE
80S ON MONDAY...WITH MID TO UPPER 80S POSSIBLE IN THE MOST
DOWNSLOPE PRONE LOCATIONS LIKE THE GENESEE VALLEY. MONDAY NIGHT WILL
REMAIN WARM /LOW IN THE UPPER 60S TO AROUND 70/...WITH SOUTHERLY
DOWNSLOPE WINDS AHEAD OF THE SURFACE FRONT KEEPING THE BOUNDARY
LAYER MIXED OVERNIGHT. THIS ALONG WITH DEW POINTS CLIMBING INTO THE
60S WILL MAKE FOR AN UNCOMFORTABLE NIGHT TO SLEEP WITH THE WINDOWS
OPEN.

TUESDAY INTO TUESDAY NIGHT...AS THE PARENT SHORTWAVE TROUGH TRACKS
NORTH OF THE FORECAST AREA...THE ATTENDANT COLD FRONT WILL EITHER
PUSH AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
FORECAST AREA...OR INCREASE THE CHANCE FOR AN MCS TRACKING OUT OF
MICHIGAN / MIDWEST TO MOVE ACROSS THE AREA. THE TIMING OF WHICH
REMAINS FAIRLY UNCERTAINTY AT THIS LEAD TIME. STILL TEMPERATURES
WILL LARGELY REMAIN IN THE LOW 80S ON TUESDAY WITH 850 MB
TEMPERATURES SURGING TO AROUND +17C AHEAD OF THE FRONT...ALTHOUGH
HEATING WILL BE LIMITED BY INCREASE CLOUD COVER AND CHANCE OF
SHOWERS AND STORMS.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
WEAK HIGH PRESSURE WILL BUILD INTO ACROSS THE AREA WEDNESDAY THROUGH
FRIDAY... THIS WILL KEEP TEMPERATURES IN THE 70S TO NEAR 80 WITH
BELOW NORMAL CHANCES OF PRECIPITATION TO END THE WORK WEEK.

LOOKING AHEAD TO NEXT WEEKEND...FORECAST CONFIDENCE REMAINS BELOW
NORMAL... AS VARIOUS FORECAST MODELS DISAGREE ON THE TIMING A
SHORTWAVE THAT COULD BRING INCREASED SHOWER/THUNDERSTORM CHANCES
TO ONE OF THE DAY OF THE WEEKEND. WHILE SATURDAY OR SUNDAY COULD
SEE SOME SHOWER/THUNDERSTORM ACTIVITY... THE WEEKEND LOOKS FAR
FROM A WASHOUT.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AN AREA OF RAIN SHOWERS WILL PASS SE OF ALL TAF SITES WITH JUST A
SMALL CHANCE OF A SHOWER THROUGH 15Z. THIS CLOSE CALL IS PROBABLY
LEADING GUIDANCE TO BE PESSIMISTIC WITH THE 00Z BUF SOUNDING
SHOWING QUITE A BIT OF DRY AIR BENEATH 15K FT. THERE IS A SMALL
CHANCE FOR SOME IFR/MVFR CIGS AT JHW...OTHERWISE VFR CONDITIONS
SHOULD PREVAIL.

SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG A BOUNDARY
INLAND OF THE LAKES TODAY...WITH A SMALL CHANCE THESE WILL BRIEFLY
IMPACT ART/ROC/JHW. OTHERWISE EXPECT VFR CONDITIONS THIS
AFTERNOON THROUGH THIS EVENING.



OUTLOOK...
SUNDAY THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS.

&&

.MARINE...
A WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE ACROSS THE LOWER
GREAT LAKES THROUGH THE HOLIDAY WEEKEND. THIS WILL GENERALLY
RESULT IN RELATIVELY LIGHT WINDS AND MINIMAL WAVES...WITH LOCAL
LAKE BREEZE CIRCULATIONS DEVELOPING EACH AFTERNOON.

&&

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

&&

$$

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



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