Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000
FXUS63 KGRR 232211
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
611 PM EDT WED JUL 23 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 PM EDT WED JUL 23 2014

COOL AND DRY CONDITIONS WILL DOMINATE THE WEATHER ACROSS LOWER
MICHIGAN THROUGH THE DAY ON FRIDAY AS HIGH PRESSURE MOVES THROUGH
THE AREA. WARMER AIR WILL TRY TO MOVE BACK INTO THE AREA OVER THE
WEEKEND. THIS WILL ALSO BRING A MORE UNSETTLED WEATHER PATTERN TO
THE AREA WITH A CHANCE OF SHOWERS AND STORMS AT TIMES OVER THE
WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 329 PM EDT WED JUL 23 2014

THE SHORT TERM PORTION OF THE FCST IS EXPECTED TO GENERALLY BE COOL
AND QUIET. THE MAIN CHALLENGE OF THE FCST IS THE CHC OF PCPN FOR FRI
NIGHT AS WE SEE WARM AND MOIST AIR TRY TO RETURN TO THE AREA.

LOW LEVEL CLOUD COVER THAT HAS BEEN IN PLACE TODAY IS SLOWLY
DIMINISHING IN COVERAGE FROM THE EDGES AND MIXING OUT AS DRIER AIR
GRADUALLY REPLACES THE RESIDUAL MOISTURE THAT WAS LEFT FROM
YESTERDAY. WE EXPECT THIS TREND TO CONTINUE INTO THE EVENING HOURS.

NOT MUCH TO TALK ABOUT FOR THE THU THROUGH FRI TIME FRAME. HIGH
PRESSURE AT THE SFC WILL BUILD IN AS UPPER RIDGING BUILDS JUST WEST
OF THE AREA FROM THE PLAINS TO THE UPPER MS VALLEY. SOME DIURNAL CU
IS EXPECTED...BUT IT SHOULD BE RATHER LIMITED IN COVERAGE. H850
TEMPS ON THU WILL BE AROUND 12C AND WILL SUPPORT TEMPS IN THE MID TO
UPPER 70S WITH A GOOD DEAL OF SUNSHINE. MANY LOCATIONS SHOULD BE
AROUND 80 ON FRI WITH H850 TEMPS WARMING A COUPLE OF DEGREES.

THE CHANCE OF SHOWERS AND STORMS WILL INCREASE ACROSS THE AREA
DURING THE FRI NIGHT TIME FRAME. THE MODELS ARE ALL KEYING IN ON A
SHORT WAVE THAT IS EXPECTED TO DIVE SE ALONG A FRONTAL SYSTEM THAT
WILL BE SW OF THE FCST AREA. THIS SHORT WAVE INITIALLY SHOULD STAY
FAR ENOUGH SW OF THE AREA TO KEEP FRI DRY. THE FRONT THEN LIFTS NE
ON FRI NIGHT AS THE UPPER LOW COMING ONSHORE OVER THE PACIFIC NW
RIDES JUST NORTH OF THE U.S./CANADIAN BORDER AND INTO THE AREA. THIS
LOW WILL BE WHAT PUSHES THE FRONT INTO THE AREA...WITH A SURGE OF
WARM AND MOIST AIR.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 329 PM EDT WED JUL 23 2014

MODELS ARE IN BETTER AGREEMENT TODAY IN REGARD TO THE LONG TERM
PERIOD OF THE FORECAST. THE GFS AND THE ECMWF ARE MORE IN LINE WITH
THE LEAD SHORTWAVE (CURRENTLY THE UPPER LOW IN THE PACIFIC
NORTHWEST) IN REGARD TO TIMING INTO THE GREAT LAKES. BOTH MODELS NOW
MOVE IT INTO THE WESTERN GREAT LAKES SATURDAY AFTERNOON AND SATURDAY
NIGHT. THIS SHORTWAVE THEN DRIVES THROUGH THE REGION ON
SUNDAY...WHICH AIDES IN DIGGING A DEEP UPPER TROUGH OVERHEAD FOR
NEXT WEEK.

HIGHLIGHTS IN THE LONG TERM ARE THE THREAT OF SHOWERS AND STORMS
OVER THE WEEKEND AS THE LEAD SHORTWAVE SWINGS THROUGH AND THEN
SHOWER CHANCES NEXT WEEK WITH THE UPPER TROUGH OVERHEAD. REGARDING
TEMPERATURES...THE WEEKEND WILL BE NEAR NORMAL WITH HIGHS UP TOWARDS
80 DEGREES...BUT WILL FALL WELL BELOW NORMAL EARLY NEXT WEEK WITH
HIGHS AROUND 70 TO THE LOWER 70S.

AS FOR THE DETAILS IN PRECIPITATION TRENDS...HAVE CHANCE POPS
SATURDAY AND SATURDAY NIGHT AS A SURFACE FRONT PUSHES EAST THROUGH
THE AREA. HIGHER POPS ON SUNDAY FOR WHEN THE MAIN UPPER SHORTWAVE
AND ASSOCIATED SURFACE LOW SWING THROUGH. HAVE SHOWERS AND STORMS
MENTIONED THROUGH THE WEEKEND WITH ENOUGH INSTABILITY AROUND FOR
CONVECTION.

NEXT WEEK...CHANCES FOR SHOWERS ARE A LITTLE BIT LOWER...BUT NOT
ZERO...WITH A DEEP UPPER TROUGH OVERHEAD. MODELS ARE NOT PAINTING
MUCH IN THE WAY OF PRECIP...BUT THIS IS LIKELY A BIT UNDERDONE GIVEN
THE LOOK OF THE UPPER TROUGH. AT THIS POINT HAVE 20-30 PCT POPS IN
PLACE MOST PERIODS EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 603 PM EDT WED JUL 23 2014

LOOKS LIKE VFR WEATHER TO PREVAIL THROUGH 00Z FRI...HOWEVER LATE
TONIGHT A RISK FOR SOME FOG EXISTS. DEWPOINTS ARE SOMEWHAT
ELEVATED COMPARED TO FORECASTED OVERNIGHT LOW TEMPERATURES. THIS
WILL NEED TO BE MONITORED. CONSIDERING THE RELATIVELY WEAK
PRESSURE GRADIENT AND HIGH SCT TO BKN CLOUD BASES...WENT WITH ONE
LINE TAFS.

&&

.MARINE...
ISSUED AT 329 PM EDT WED JUL 23 2014

WE WILL BE LEAVING ALL MARINE HEADLINES UP AND UNCHANGED FOR THIS
FCST PACKAGE. WE HAVE SEEN A LITTLE INCREASE IN WAVE ACTION THIS
AFTERNOON AS THE FLOW HAS SHIFTED FROM NNE TO MORE NNW ALLOWING FOR
A MUCH LONGER FETCH AND FOR BETTER WAVES OFFSHORE TO MAKE IT INTO
THE NEARSHORE AREAS. WINDS SHOULD DIMINISH EARLY THIS EVENING...WITH
WAVES FOLLOWING SUIT SHORTLY THEREAFTER.

THE NEXT PERIOD OF CONCERN FOR MARINE INTERESTS WILL BE ON FRI NIGHT
AND SAT AS THE NEXT SYSTEM APPROACHES THE AREA. WE WILL SEE WINDS
GRADUALLY INCREASE AT THAT POINT...AND SMALL CRAFT ADVISORY
CONDITIONS WILL BE POSSIBLE.


&&

.HYDROLOGY...
ISSUED AT 329 PM EDT WED JUL 23 2014

NO HYDROLOGY ISSUES ARE EXPECTED THROUGH THE END OF THE WEEK AS DRY
WEATHER IS EXPECTED THROUGH FRI. RAINFALL FROM LAST NIGHT OF 1 TO 2
INCHES ALONG THE LAKESHORE DOES NOT LOOK TO HAVE CAUSED SIGNIFICANT
ISSUES. IT WILL JUST KEEP RIVER AND STREAM LEVELS ABOVE AVERAGE TO
MUCH ABOVE AVERAGE...WITHOUT ANY FLOODING EXPECTED AT THIS TIME.
RIVERS AND STREAMS WILL HAVE A CHANCE TO RECOVER A BIT THROUGH THE
END OF THE WEEK.

PCPN CHCS WILL RETURN TO THE AREA FRI NIGHT/SAT. PRECIPITATION
CHANCES AND AMOUNTS ARE STILL A BIT OF UNCERTAIN...SO EFFECTS ON THE
RIVERS ARE ALSO UNCERTAIN. THIS WILL CONTINUED TO BE MONITORED.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH THURSDAY MORNING FOR MIZ056-064-
     071.

     BEACH HAZARDS STATEMENT UNTIL 2 AM EDT THURSDAY FOR MIZ037-043-
     050.

LM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR LMZ847>849.

     SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LMZ844>846.

&&

$$

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






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