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000
FXUS63 KGRR 300322
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1122 PM EDT TUE JUL 29 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 PM EDT TUE JUL 29 2014

UNSEASONABLY COOL WEATHER WILL LINGER A FEW MORE DAYS BUT WILL
REBOUND TO NEAR NORMAL FOR THE END OF THE WEEK AND OVER THE WEEKEND.
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH DAY
THIS WEEK... PARTICULARLY IN THE AFTERNOON AND EVENING AND INLAND
FROM LAKE MICHIGAN.

&&

.UPDATE...
ISSUED AT 919 PM EDT TUE JUL 29 2014

NO MAJOR UPDATES TO THE FCST THIS EVENING. WE HAVE JUST PULLED OUT
THE THUNDER MENTION FROM THE FCST AS DIURNAL INSTABILITY IS LOST
AS EXPECTED. A FEW LIGHT SHOWERS REMAIN POSSIBLE LATER TONIGHT AS THE
NEXT SHORT WAVE DIVES IN FROM THE NW.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM EDT TUE JUL 29 2014

SCATTERED DIURNAL CONVECTION HAS DEVELOPED EAST OF HWY 131
UNDERNEATH UPPER TROUGH/COLD POOL ALOFT AND WILL CONTINUE THROUGH
SUNSET WITH AN OVERALL EASTWARD DRIFT BEFORE DISSIPATING.

WHILE THE LAKESHORE COUNTIES HAVE BEEN SPARED OF ANY DIURNAL
ACTIVITY DUE TO THE STABLE ONSHORE FLOW... THIS AREA IS STILL AT
RISK FOR SOME SHOWERS AFTER 7-8 PM THIS EVENING AS THE CONVECTION
CURRENTLY DEVELOPING IN NORTHERN WISCONSIN SLIDES SOUTHEAST ACROSS
LK MI IN A DECAYING MODE.

THE PROBABILITY/COVERAGE OF SHOWERS AND TSTMS ON WEDNESDAY LOOKS
LESS THAN TODAY AS MODELS CONTINUE TO SHOW BEST SFC CONVERGENCE
ALONG AND SOUTH OF I-94. WILL HAVE CHANCE POPS SOUTH AND EAST OF
GRR... DECREASING WEST AND NORTH OF GRR.

WHILE THE COVERAGE/INTENSITY OF CONVECTION WILL CERTAINLY BE LESS
LATE AT NIGHT INTO MID MORNING OVER THE NEXT 72 HRS... FEEL SOME LOW
POPS MAY STILL BE WARRANTED OUTSIDE OF PK HEATING TIME. MODELS/WATER
VAPOR IMAGERY SHOW SEVERAL WEAK SHORTWAVES/VORT MAXES ROTATING
AROUND THE HUDSON BAY VORTEX. ANY ONE OF THESE FEATURES COULD STILL
TOUCH OFF A FEW SHOWERS AT ANY TIME AS THEY SLIDE SOUTHEAST THROUGH
THE GREAT LAKES REGION... EVEN WITHOUT THE DIURNAL COMPONENT.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 PM EDT TUE JUL 29 2014

OVERALL THE SAME GENERAL WX PATTERN WILL PERSIST THROUGH THE LONG
RANGE FORECAST PERIOD FEATURING A PERSISTENT UPPER LEVEL TROUGH OVER
THE GREAT LAKES REGION IN RESPONSE TO THE HIGH AMPLITUDE RIDGE OUT
WEST. THE UPPER TROUGH WILL BE MOST AMPLIFIED OVER OUR REGION FRIDAY
THROUGH THE WEEKEND. HOWEVER TEMPS SHOULD AVERAGE CLOSE TO NORMAL IN
SPITE OF THAT.

INSTABILITY DUE TO DAYTIME HEATING AND WITH COLD AIR ALOFT UNDER THE
UPPER TROUGH MAY LEAD TO A FEW DIURNALLY DRIVEN SHOWERS AND PERHAPS
A FEW ISOLATED STORMS DURING THE AFTERNOON AND EARLY EVENING HOURS.

THERE WILL STILL BE SOME INFLUENCE FROM THE UPPER TROUGH INTO EARLY
NEXT WEEK. HOWEVER THE UPPER TROUGH AXIS AND POOL OF COLDER AIR
ALOFT SHOULD SHIFT NE TO QUEBEC. TEMPS WILL CONTINUE TO AVERAGE
QUITE CLOSE TO NORMAL EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1122 PM EDT TUE JUL 29 2014

NOT TO MUCH CHANGE IN MY THINKING EXPECT I ADDED SOME MVFR MIST IN
THE TAFS AROUND SUNRISE AS WINDS AREA LIGHT AND TEMPERATURES
SHOULD BE GETTING CLOSE THE DEW POINT. THE SHORTWAVE FROM SOUTHERN
CANADA SHOULD BRING A BAND OF CLOUDS THROUGH THE CWA TOWARD
MORNING BUT IT WILL NOT LAST LONG.... ONCE THE SECONDARY COLD FRONT
COMES THROUGH SKIES SHOULD CLEAR. ONLY A FEW AFTERNOON CUMULUS
CLOUDS ARE EXPECTED.

&&

.MARINE...
ISSUED AT 330 PM EDT TUE JUL 29 2014

TWO NORTH FLOW UPWELLING/OVERTURNING EVENTS IN THE LAST WEEK HAS
RESULTED IN VERY COLD WATER TEMPS IN THE 40S DEVELOPING ALONG THE
COAST PER BUOY READINGS. THIS IS ACTUALLY RESULTING IN SOME PATCHY
DENSE FOG AS SHOWN ON THE MUSKEGON WEB CAM DESPITE A COOL AND
RELATIVELY DRY AIR MASS.

SFC DEW PTS HOWEVER ARE IN THE MID 50S WHICH OVER 40 DEGREE WATER
WITH WINDS 10 KTS OR LESS IS PROMOTING SOME FOG. HAVE ADDED THIS
THREAT TO THE NEARSHORE FCST OVER THE NEXT FEW DAYS. PERIODS OF
STRONGER WINDS IN THE AFTERNOON AND EARLY EVENING MAY MIX THE FOG
OUT AT TIMES. CONFIDENCE IN COVERAGE AND PERSISTENCE OF THE FOG IS
LOW... SO WILL NOT ISSUE A MARINE DENSE FOG ADVISORY.

NO SIGNIFICANT WINDS/WAVES EXPECTED OVER THE NEXT FEW DAYS WHICH
WOULD NECESSITATE SMALL CRAFT ADVISORIES.


&&

.HYDROLOGY...
ISSUED AT 330 PM EDT TUE JUL 29 2014

NO HYDRO CONCERNS AT THIS TIME GIVEN WIDELY SCATTERED NATURE OF
THE CONVECTION OVER THE NEXT FEW DAYS. SOME BRIEF LOCALLY HEAVY
DOWNPOURS WITH SMALL HAIL MAY OCCUR IN ANY OF THE HEALTHIER CELLS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...NJJ
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...WDM
HYDROLOGY...MEADE
MARINE...MEADE