Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 251735
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
135 PM 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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 135 PM EDT TUE AUG 25 2015

MORE CLOUD COVER AND A FEW SHOWERS CAN BE EXPECTED OVER THE 18Z
FCST PERIOD. ONE WAVE IS MOVING OUT THIS AFTERNOON...AND
CONDITIONS ARE TRYING TO IMPROVE SLIGHTLY. WE ARE LOOKING FOR MORE
WIDESPREAD MVFR CONDITIONS TO IMPROVE TO VFR AS THE LIMITED
HEATING TAKES PLACE. SOME INSTABILITY SHOWERS COULD POP UP AT
INLAND LOCATIONS...BUT NOT ALL LOCATIONS WILL SEE THESE. SOME
BRIEF LOWER CONDITIONS WILL BE POSSIBLE UNDER THESE SHOWERS.

THE INSTABILITY SHOWERS WILL LIKELY END TOWARD SUNSET THIS
EVENING AS WILL ANY WIND GUSTS THAT KICK UP. WE WILL LIKELY STAY
VFR FOR A BIT BEFORE GOING DOWN TO MVFR OVERNIGHT AS ANOTHER WAVE
MOVES IN AND AS WE COOL DOWN. THIS WILL CONTINUE INTO WED MORNING.
WE EXPECT TO SEE IMPROVEMENT ON WED AFTERNOON...HOWEVER IT LOOKS
LIKE IT WILL BE AROUND OR AFTER 18Z WED.

&&

.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 1240 PM EDT TUE AUG 25 2015

WITH LIGHT RAIN FORECAST INTO WEDNESDAY FOLLOWED BY DRY WEATHER
THURSDAY/FRIDAY AND MORE LIGHT RAIN FRIDAY NIGHT INTO SATURDAY...
RIVER LEVELS WILL REMAIN LOW INTO NEXT WEEK WITH NO FLOODING
CONCERNS.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT 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...NJJ
HYDROLOGY...63
MARINE...MEADE



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