Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 270729
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
330 AM EDT MON JUL 27 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE

.SYNOPSIS...
ISSUED AT 330 AM EDT MON JUL 27 2015

THE HEAT WILL BE THE MAIN STORY EARLY THIS WEEK WITH HIGH
TEMPERATURES PUSHING TO AROUND 90 BOTH TODAY AND ON TUESDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE WEST TUESDAY NIGHT AND MOVE
THROUGH ON WEDNESDAY. SHOWERS AND STORMS WILL BECOME POSSIBLE
BEGINNING LATE TUESDAY NIGHT AND LASTING THROUGH WEDNESDAY. LOCALLY
HEAVY RAINS ARE POSSIBLE WITH THE STRONGER STORMS. IT WILL TURN A
BIT COOLER AND DRIER FOR THURSDAY AS HIGH PRESSURE NOSES BACK INTO
THE REGION. HIGHS WEDNESDAY AND THURSDAY WILL BE BACK TOWARD
SEASONAL NORMALS IN THE LOWER TO MIDDLE 80S.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 330 AM EDT MON JUL 27 2015

FORECAST FOCUS IS ON THE SHOWERS AND STORMS IN THE FORECAST FOR
TUESDAY NIGHT AND WEDNESDAY. THE BULK OF THE CONVECTION WILL BE
COMING THROUGH DURING THE DIURNAL MINIMUM OF OVERNIGHT/MORNING.
EXPECTING SOME FADING CONVECTION TO MOVE INTO THE NORTHWEST CWA
OVERNIGHT. MOST UNSTABLE CAPE VALUES ARE NOT IMPRESSIVE TUESDAY
NIGHT WITH AROUND 500 J/KG PROGD BY THE GFS. THE LEFT OVER MORNING
SHOWERS AND SCATTERED STORMS AND ASSOCIATED CLOUD COVER WILL LIKELY
TEMPER WEDNESDAY AFTERNOON INSTABILITY. THE GFS DOES INDICATE
AIRMASS RECOVERY THROUGH WITH MOST UNSTABLE CAPE VALUES RISING TO IN
EXCESS OF 2000 J/KG. THINK THIS MIGHT BE A BIT OVERDONE GIVEN THE
AFOREMENTIONED REASONS.

NOT EXPECTING SEVERE WITH THIS SYSTEM GIVEN THE MAIN UPPER SUPPORT
IS LOCATED WELL NORTH OF THE FORECAST AREA AND INSTABILITY IS GOING
TO BE QUESTIONABLE. BETTER DEEP LAYER SHEAR LAGS THE FRONT...SO NOT
EXPECTING ORGANIZED STORMS. SCATTERED SINGLE CELL AND MULTI-CELL
STORMS MOST LIKELY. THE WAY WE COULD SEE STRONG STORMS IS IF THE
PRECIP TUESDAY NIGHT IS LESS THAN PROGD AND WE CAN DESTABILIZE
WEDNESDAY MORNING AHEAD OF THE COLD FRONT. THIS SEEMS UNLIKELY AND
WE WILL STILL HAVE WEAK SHEAR IN PLACE.

STILL LOOKING AT HOT TEMPERATURES TODAY AND TUESDAY. MOST LIKELY
AROUND 90 IN MOST AREAS TODAY OUTSIDE OF THE WESTERN LAKE SHORE
COUNTIES WHERE A LAKE BREEZE PUSHES IN THIS AFTERNOON. TUESDAY I AM
STILL A BIT CONCERNED ABOUT UPSTREAM CLOUDS PRESSING IN. AROUND 90
SEEMS FAIR FOR TUESDAY AS WELL THOUGH WITH WARM 850MB TEMPS IN THE
+18 T0 +19 C RANGE.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM EDT MON JUL 27 2015

WE ARE LOOKING AT A QUIET PERIOD OF WEATHER AT THE BEGINNING OF THE
LONG TERM PORTION OF THE FCST. THE END OF THE LONG TERM LOOKS TO
BECOME A BIT UNSETTLED WITH CHCS OF SHOWERS AND STORMS ARRIVING FOR
NEXT WEEKEND.

WE CONTINUE TO THINK THAT THE RAIN CHCS WILL BE EAST OF THE AREA BY
THE BEGINNING OF THE LONG TERM ON WED NIGHT. MODELS ARE IN GOOD
AGREEMENT WITH HAVING THE FRONT EAST OF THE AREA BY 00Z THU. WE DO
SEE GENERAL TROUGHING MOVE IN AT THE UPPER LEVELS...BUT THE JET CORE
REMAINS NORTH OF THE CWFA SO ADDITIONAL RAIN LOOKS VERY UNLIKELY. WE

WILL SEE THE DRY CONDITIONS AND MILD WEATHER LIKELY STICK AROUND
THROUGH FRI NIGHT. THE LONG WAVE TROUGH AXIS WILL SHIFT EAST OF THE
AREA...PUTTING LOWER MICHIGAN UNDER NW FLOW DOWNSTREAM OF THE UPPER
RIDGE AXIS WELL WEST OF THE AREA. SHORT WAVES IN THE UPPER FLOW
SHOULD GENERALLY REMAIN NORTH OF THE AREA AND DAMPEN COMING OVER THE
RIDGE. THE GOOD MOISTURE WILL ALSO REMAIN LOCKED UP SOUTH OF THE
AREA DURING THIS TIME FRAME.

WE WILL SEE THE CHCS FOR SHOWERS AND STORMS INCREASE A BIT FOR NEXT
WEEKEND. THE RIDGE TO OUR WEST RETROGRADES WEST AND FLATTENS A
BIT...RESULTING IN A MORE ZONAL FLOW OVER THE AREA. WE WILL SEE
SHORT WAVES SURVIVE A LITTLE BETTER AND AFFECT THE AREA. THESE
THINGS COMBINED WITH SOME MOIST ADVECTION COMING FROM THE GULF WILL
HELP TO INCREASE THE THREAT FOR SHOWERS/STORMS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 152 AM EDT MON JUL 27 2015

WE ARE EXPECTING MAINLY VFR CONDITIONS FOR MOST OF THE SITES
THROUGH THIS FCST PERIOD. SKIES WILL BE MAINLY CLEAR OVERNIGHT
TONIGHT. THERE IS SOME POTENTIAL FOR FOG TONIGHT GIVEN THE DEW
POINTS WELL IN THE 60S AND LIGHT WINDS. WE HAVE LEFT IT OUT OF THE
FCST WITH THE DRY CONDITIONS FROM SUN AFTERNOON AND WITH LIMITED
FOG LAST NIGHT. WE DID PUT IT IN AT KJXN SINCE IT IS
CLIMATOLOGICALLY FAVORED THERE ON NIGHTS LIKE TONIGHT AND SINCE
THEY DID HAVE SOME LAST NIGHT.

AFTER ANY FOG DISSIPATES AFTER SUNRISE THIS MORNING...QUIET
CONDITIONS WILL CONTINUE. ONLY A LITTLE CUMULUS DEVELOPMENT
EXPECTED WITH MAINLY LIGHT E/SE WINDS. A LAKE BREEZE WILL DEVELOP
IN THE AFTERNOON ALONG THE LAKESHORE.

&&

.MARINE...
ISSUED AT 330 AM EDT MON JUL 27 2015

VERY QUIET MARINE CONDITIONS ARE EXPECTED ON LAKE MICHIGAN BOTH
TODAY AND TONIGHT. WINDS WILL GENERALLY BE LESS THAN 10 KNOTS. THE
EXCEPTION WILL BE THE LAKE BREEZE THIS AFTERNOON WHERE SPEEDS MAY
BRIEFLY TOUCH THE 10-15 KNOT RANGE. WAVES WILL BE A FOOT OR LESS
THROUGH TONIGHT.

WINDS LOOK FAIRLY LIGHT ON TUESDAY NOW AS WELL AS THE GRADIENT
REALLY DOESNT BUILD IN UNTIL AFTER DARK. TWO FOOTERS OR
LESS ON TUESDAY.

SOUTHERLY FLOW TUESDAY NIGHT INTO WEDNESDAY MORNING WILL PUSH WAVES
INTO THE 1 TO 3 FOOT RANGE IT APPEARS. WINDS WILL COME UP OUT OF THE
WEST ON WEDNESDAY BEHIND THE COLD FRONT WITH WAVES THAT MAY BUILD
INTO THE 2 TO 4 FOOT RANGE.

&&

.HYDROLOGY...
ISSUED AT 1053 AM EDT SUN JUL 26 2015

HYDRO WORLD CONTINUES TO BE UNEVENTFUL WITH NO CONCERNS UNTIL
TUESDAY NIGHT AND WEDNESDAY.

DRY WEATHER WILL CONTINUE TODAY THROUGH MUCH OF TUESDAY BEFORE
THE NEXT CHANCE OF RAIN APPROACHES TUESDAY NIGHT INTO WEDNESDAY.
THE MID-WEEK EVENT DOES NOT LOOK TOO IMPRESSIVE FOR WIDESPREAD
HEAVIER RAINFALL...BUT LOCALLY HEAVY RAIN MAY BE POSSIBLE WHEN
THE TIME COMES. STREAMS AND RIVERS ARE RUNNING WELL BELOW ANY
PRODUCT CRITERIA AND WILL BE ABLE TO HANDLE WHAT IS FORECAST.

&&

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

$$

SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...JAM
MARINE...DUKE



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