Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 020530
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
130 AM EDT WED SEP 2 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 328 PM EDT TUE SEP 1 2015

HAZY HOT AND HUMID WEATHER WILL CONTINUE FOR MUCH OF THIS WEEK AS A
PERSISTENT UPPER RIDGE REMAINS ENTRENCHED OVER THE GREAT LAKES.
HIGHS IN THE MID TO UPPER 80S COUPLED WITH DEWPOINTS AROUND 70 WILL
FEEL MORE LIKE EARLY AUGUST USUALLY DOES. LOW CHANCES FOR SHOWERS AN
STORMS EXIST HOWEVER BUT SEVERE STORMS ARE NOT EXPECTED.

&&

.UPDATE...
ISSUED AT 127 AM EDT WED SEP 2 2015

ISSUED AN EARLY MORNING UPDATE. A COUPLE OF SHOWERS HAVE DEVELOPED
BETWEEN MUSKEGON AND LUDINGTON. THEY WERE TRACKING SLOWLY EAST. AS
A RESULT I ADDED A SMALL CHANCE FOR A SHOWER TO MUCH OF THE
FORECAST AREA.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 328 PM EDT TUE SEP 1 2015

FORECAST CONCERNS DEAL WITH MINOR CHANCES FOR STORMS WEDNESDAY NIGHT
THROUGH THURSDAY NIGHT.

LATEST WV LOOP SHOWS A WELL DEFINED UPPER LOW SPINNING OVER CENTRAL
INDIANA. THERE HAS BEEN PERSISTENT CONFECTION DEVELOPING AROUND THE
LOW BUT ALL OF IT HAS REMAINED SOUTH OF THE CWA AND WILL CONTINUE TO
DO SO TONIGHT. ABUNDANT CAPE HAS DEVELOPED OVER THE CWA WITH
MESOANALYSIS SHOWING 3000 J/KG ACROSS THE CWA. HOWEVER...WITH NOT
MUCH OF A KICKER OUTSIDE OF THE LAKE BREEZE THERE ISN`T ENOUGH LIFT
TO TAKE ADVANTAGE OF THE INSTABILITY. INSTEAD...DEWPOINTS WILL
REMAIN HIGH OVERNIGHT AND AREAS OF FOG ARE EXPECTED.

A SHORT WAVE CURRENTLY OVER NORTHEAST NEBRASKA WILL SLOWLY MOVE
TOWARD EASTERN WISCONSIN AND THEN ACROSS LAKE MICHIGAN WEDNESDAY
NIGHT AND THURSDAY. AFTER A DRY DAY TOMORROW ISOLATED TO SCATTERED
STORMS ARE EXPECTED WEDNESDAY NIGHT AND THURSDAY AS THIS WAVE MOVES
ACROSS. CLOUDS ASSOCIATED WITH THE WAVE WILL LIKELY HOLD HIGHS IN
THE MID VS UPPER 80S THURSDAY. SHORT RANGE MODELS SHOW THIS WAVE
VERY SLOW TO MOVE OUT OF THE CWA SO WE/LL CONTINUE WITH LOW POPS
THURSDAY NIGHT TOO.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 328 PM EDT TUE SEP 1 2015

LABOR DAY WEEKEND WILL CONTINUE TO FEATURE UNSEASONABLY WARM AND
HUMID CONDITIONS ALONG WITH A DAILY RISK OF A FEW POP UP SHOWERS OR
NON SEVERE THUNDERSTORMS.

LATEST MEDIUM RANGE GUIDANCE INDICATES THAT THE SHORTWAVE WHICH
COMES INTO THE STATE ON THURSDAY STALLS AND ACTUALLY BECOMES A WEAK
CUTOFF LOW OVER MICHIGAN ON FRIDAY... UNDERNEATH THE BUILDING UPPER
RIDGE. THIS FEATURE LOOKS TO LIFT BACK TO THE NORTH SATURDAY AND
GETS ABSORBED WITH THE STRONGER WESTERLIES OVER CANADA DUE TO
DEVELOPING SOUTH FLOW ALOFT AROUND A STRENGTHENING UPR HIGH CENTER
OVER NEW YORK. HOWEVER ADDITIONAL WEAK VORTICITY MAXIMA ARE SENT OUR
WAY OVER THE HOLIDAY WEEKEND FROM THE MID ATLANTIC REGION ON THE SRN
AND WRN PERIPHERY OF THE AFOREMENTIONED UPR HIGH CENTER.

THESE WEAK VORTICITY MAXIMA ALOFT... COMBINED WITH DAILY MESOSCALE
FEATURES WHICH MANAGE TO CREATE SFC CONVERGENCE SUCH AS THE LAKE
BREEZE OR OUTFLOW BOUNDARIES... COULD BE AN IMPETUS FOR CONVECTION.
SFC COLD FRONT APPROACHING FROM THE WEST LATE MONDAY MAY PROVIDE A
BETTER FOCUS FOR STORMS BUT THE TIMING AND STRENGTH OF THE FRONT IS
QUESTIONABLE AT THIS TIME.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1154 PM EDT TUE SEP 1 2015

CONDITIONS WILL GRADUALLY DETERIORATE TO A MIX OF MVFR/IFR DURING
THE EARLY TO MID MORNING HOURS DUE TO DEVELOPMENT OF PATCHY FOG.
FOG WILL DISSIPATE DURING THE MID TO LATE MORNING HOURS WHEN
CONDITIONS WILL GRADUALLY IMPROVE TO MVFR THEN VFR FOR WEDNESDAY
AFTERNOON.

A FEW SHOWERS AND THUNDERSTORMS MAY DEVELOP FROM MID AFTERNOON
WEDNESDAY THROUGH WEDNESDAY EVENING. HOWEVER THERE IS NOT ENOUGH
POTENTIAL FOR RAIN OR THUNDERSTORMS TO WARRANT INCLUSION IN ANY OF
THE TERMINAL FORECASTS AT THIS TIME.


&&

.MARINE...
ISSUED AT 328 PM EDT TUE SEP 1 2015

UPPER RIDGE WILL KEEP WINDS UNDER 20KTS RESULTING IN WAVES 1-3 FEET
FOR THE NEXT FEW DAYS.


&&

.HYDROLOGY...
ISSUED AT 302 AM EDT TUE SEP 1 2015

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAY OCCUR OVER THE
NEXT SEVERAL DAYS. THERE REMAINS A BIT OF UNCERTAINTY WITH THEIR
COVERAGE AND INTENSITY. WIDESPREAD HEAVY RAINFALL IS NOT EXPECTED...
BUT AS IS THE CASE WITH SUMMER THUNDERSTORMS... LOCALLY HEAVY RAIN
AND MINOR FLOODING IMPACTS ARE NOT OUT OF THE QUESTION.

&&

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

$$

UPDATE...MJS
SYNOPSIS...04
SHORT TERM...04
LONG TERM...MEADE
AVIATION...LAURENS
HYDROLOGY...CAS
MARINE...04


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