Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 251109
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
709 AM EDT TUE AUG 25 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 330 AM EDT TUE AUG 25 2015

A LARGE SLOW MOVING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT
LAKES REGION WILL CONTINUE TO PRODUCE CLOUDS AND SCATTERED SHOWERS
THROUGH WEDNESDAY ALONG WITH COOL TEMPERATURES IN THE 60S.

SUNSHINE AND MILDER TEMPERATURES WILL RETURN ON THURSDAY AS THE LOW
FINALLY MOVES OUT AND IS REPLACED BY HIGH PRESSURE. CURRENTLY THE
WEEKEND LOOKS WARM WITH HIGHS NEAR 80 AND ONLY A SLIGHT CHANCE FOR A
SHOWER OR THUNDERSTORM.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 330 AM EDT TUE AUG 25 2015

CLOUDS AND SCATTERED SHOWERS CAN BE EXPECTED TODAY RELATED TO THE
BROAD TROUGHING AND COOL AIR ALOFT. HOWEVER FCST SOUNDINGS SHOW A
STRONG CAPPING INVERSION PRESENT AT AROUND 5000 FT INDICATING THAT
THE SHOWERS WILL BE RELATIVELY SHALLOW AND THEREFORE PREDOMINATELY
ON THE LIGHTER SIDE.

INVERSION HEIGHTS ARE A BIT HIGHER TODAY NORTHEAST OF GRR CLOSER TO
THE UPPER LOW...AROUND 7000 FT....SO SHOWERS AROUND CLARE AND MT
PLEASANT COULD BE A BIT HEALTHIER AND MORE NUMEROUS THAN THOSE SOUTH
OF I-96... ESPECIALLY IF ANY BREAKS IN THE OVERCAST PERMIT SOME
DIURNAL ENHANCEMENT THIS AFTERNOON.

THE CORE OF THE COLDEST AIR AT H8... AROUND 4C... IS MOVING THROUGH
THIS MORNING AND RESULTING IN A FEW MODERATE LAKE ENHANCED SHOWERS
ALONG/NEAR THE I-96 CORRIDOR. THE LAKE INFLUENCE SHOULD LESSEN WITH
TIME THIS AFTERNOON AS H8 TEMPS SLOWLY WARM... AND AS CURRENTLY
ENHANCED LOW LEVEL CONVERGENCE IS LOST ONCE THE BOUNDARY LAYER WINDS
INCREASE UNIFORMLY TO 10-20 MPH AREA WIDE.

EXTENSIVE CLOUDS EXPECTED TO LINGER ON WEDNESDAY WITH COOL/MOIST
CYCLONIC FLOW STILL IMPACTING THE AREA. HOWEVER THE UPPER TROUGH
AXIS WILL BE TO OUR EAST AND THE COVERAGE/INTENSITY OF SHOWERS WILL
BE LESS THAN TODAY WITH SHALLOWER MOISTURE PROFILES PROGGED.
THINKING PRIMARILY JUST SCATTERED SPRINKLES FOR WEDNESDAY.

SFC RIDGING AND DRIER AIR ARRIVE WEDNESDAY NIGHT AND THURSDAY FROM
THE NORTHWEST... YIELDING DECREASING CLOUD PATTERN.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 AM EDT TUE AUG 25 2015

HIGH PRESSURE WILL BEGIN MOVING EAST THURSDAY NIGHT. IN RESPONSE LOW
PRESSURE OVER THE PLAINS WILL FOLLOW BUT WEAKEN AS IT APPROACHES THE
GREAT LAKES. THEREFORE CHANCES FOR RAIN AREN`T GREAT AND ARE
REFLECTED BY LOW POPS IN THE GRIDS. THE SYSTEM DOES HAVE SOME WEAK
SHORTWAVE SUPPORT ALOFT FRIDAY NIGHT AND SATURDAY HOWEVER AND WHEN
COUPLED WITH 500 J/KG MUCAPE MAY BE ENOUGH TO KICK OFF A SHOWER OR
STORM. THE SYSTEM WILL BE OUT OF THE GREAT LAKES BY LATE IN THE
WEEKEND AND HIGH PRESSURE WILL NOSE INTO THE CWA. THAT MEANS HIGHER
HEIGHTS AND SFC TEMPS WITH A RETURN TO MID 80S HIGHS BY MONDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 709 AM EDT TUE AUG 25 2015

MVFR TO VFR OVERCAST CIGS OF GENERALLY 2500-4000 FT ARE EXPECTED
TODAY AND TONIGHT ALONG WITH SCATTERED RAIN SHOWERS. THE SHOWERS
WILL BE PREDOMINATELY LIGHT AND NO SIGNIFICANT REDUCTIONS TO
VISIBILITIES ARE ANTICIPATED. IF THE VSBY IN A SHOWER DOES DIP
BELOW 6 MILES... IT SHOULD BE ONLY FOR A BRIEF DURATION. WEST TO
NORTHWEST SFC WINDS WILL BE MUCH LIGHTER TODAY THAN THEY WERE ON
MONDAY... AT 5 TO 15 KTS.

&&

.MARINE...
ISSUED AT 330 AM EDT TUE AUG 25 2015

SMALL CRAFT ADVISORIES/BEACH HAZARD STATEMENTS CONTINUE TODAY WITH
NORTHWEST WINDS OF 15 TO 25 KTS AND WAVES 3-6 FEET. WINDS AND WAVES
ARE EXPECTED TO DIMINISH BELOW ADVISORY CRITERIA TONIGHT AND
WEDNESDAY ALTHOUGH STILL SOME 2-4 FOOTERS LIKELY. WATERSPOUTS CANNOT
BE RULED OUT TODAY... ESPECIALLY OVER CENTRAL AND NRN LK MICHIGAN...
BUT RELATIVELY SHALLOW CONVECTIVE CLOUD DEPTHS IS A LIMITING FACTOR.


&&

.HYDROLOGY...
ISSUED AT 1226 PM EDT MON AUG 24 2015

SCATTERED SHOWERS ARE POSSIBLE THIS AFTERNOON THROUGH
TONIGHT...BUT THE BEST COVERAGE WILL BE TUESDAY-TUESDAY NIGHT. NO
SIGNIFICANT HYDRO IMPACTS EXPECTED FROM THIS RAINFALL. DRY WEATHER
WILL PREVAIL TOWARD THE END OF THE WEEK WITH HIGH PRESSURE IN
PLACE.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ037-043-050-
     056-064-071.

LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.

&&

$$

SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...04
AVIATION...MEADE
HYDROLOGY...EBW
MARINE...MEADE


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