Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 231759
AFDGRR

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

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 320 AM EDT WED JUL 23 2014

A COLD FRONT MOVING THROUGH SOUTHERN LOWER MICHIGAN WILL USHER IN
COOLER AND DRIER AIR FOR THE NEXT FEW DAYS. DRY WEATHER IS EXPECTED
THROUGH FRIDAY BEFORE LOW PRESSURE MOVES TOWARD THE REGION AND
BRINGS A CHANCE OF SHOWERS/STORMS OVER THE WEEKEND.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 320 AM EDT WED JUL 23 2014

FORECAST CONCERNS ARE MINIMAL TODAY NOW THAT THE COLD FRONT IS
PASSING THROUGH THE SOUTHERN CWA.

THE NEXT FEW DAYS WILL BE MUCH LESS HUMID AS DEW POINTS FALL FROM THE
UPPER 60S BACK TO THE UPPER 40S LATER TODAY. TEMPS WILL ALSO BE MUCH
COOLER WITH HIGHS IN THE MID 70S THROUGH FRIDAY.

LATEST IR LOOP SHOWS CONVECTIVE DEBRIS CLOUDS MOVING SOUTH ACROSS
LOWER MICHIGAN. THESE CLOUDS WILL EXIT THE CWA LATER THIS MORNING
LEADING TO MOSTLY SUNNY SKIES. AS HIGH PRESSURE DRIFTS OVER THE
STATE FAIR SKIES ARE EXPECTED THROUGH THURSDAY NIGHT.

AN INCREASE IN CLOUDS WILL OCCUR LATE FRIDAY AS LOW PRESSURE MOVES
EAST FROM THE PLAINS TOWARD THE GREAT LAKES. SHORT RANGE MODELS SHOW
THIS PCPN HOLDING OFF UNTIL FRIDAY NIGHT/SATURDAY.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 320 AM EDT WED JUL 23 2014

LITTLE QUESTION A COOLER THAN NORMAL TEMPERATURE PATTERN WILL
PERSIST THROUGH THE LONG TERM FORECAST PERIOD. IT WOULD ALSO SEEM
THERE IS A GOOD CHANCE OF SHOWERS SATURDAY INTO MONDAY...A FEW
THUNDERSTORMS WOULD NOT BE OUT OF THE QUESTION.

THE MODELS ARE IN OVERALL GOOD AGREEMENT WITH AN AMPLIFICATION OF
THE UPPER AIR PATTERN OVER THE WEEKEND INTO EARLY NEXT WEEK. AS IT
TURNS OUT THE RECURVING OF TYPHOON MATMO MAY WELL BE A LARGE PART OF
THE REASON FOR THIS. RECENT PUBLISHED RESEARCH NOW SHOWS RECURVING
PACIFIC TYPHOONS... THROUGH ROSSBY WAVE PROPAGATION... CAUSE A
TROUGH TO DEVELOP OVER EASTERN NORTH AMERICA ABOUT 5 DAYS AFTER THE
STORM RECURVES. THIS HAPPENED RECENTLY AFTER TYPHOON NEOGURI
RECURVED DURING THE FIRST WEEK OF JULY. GIVEN HOW THE MODELS
UNDERPLAYED THE DEVELOPMENT OF THAT TROUGH AT LONGER RANGES I HAVE
TO BELIEVE THE SLOWER AND DEEPER ECMWF HAS THE BEST HANDEL HOW
THIS WILL ALL PLAY OUT OVER THE NEXT 5 TO 7 DAYS.

AS FOR THE DETAILS DAY TO DAY... THERE IS A SYSTEM COMING ONSHORE
NEAR THE WASHINGTON COAST AS I WRITE THIS. THAT SYSTEM RIDES OVER
THE LONGWAVE RIDGE INTO FRIDAY THEN HELPS TO AMPLIFY THE EASTERN
TROUGH AS IT MERGES WITH THE MUCH LARGER CIRCULATION GOING ON OVER
EASTERN CANADA. AS THIS SYSTEM COMES INTO THE GREAT LAKES WE GET THE
WARM ADVECTION PRECIPITATION LATER FRIDAY NIGHT OR MORE LIKELY
SATURDAY. THEN AS THE NORTHERN AND SOUTHERN STREAM SYSTEMS WRAP UP
TOGETHER WE GET WRAP AROUND SHOWERS STARTING SUNDAY AND LIKELY
CONTINUING INTO MONDAY. GIVEN THAT THIS UPPER LOW DOES NOT GET
DISLODGED THROUGH MID WEEK I COULD SEE SCATTERED SHOWERS LASTING
THROUGH A GOOD PART OF NEXT WEEK BUT TEMPERATURES WILL BE AT LEAST
10 DEGREES BELOW NORMAL FROM MONDAY ON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 158 PM EDT WED JUL 23 2014

LIMITED AVIATION CONCERNS THE NEXT 24 HOURS WITH MAINLY VFR
CONDITIONS FORECAST TO PREVAIL. MVFR CONDITIONS MAY LINGER FOR AN
HOUR OR SO AT KJXN THIS AFTERNOON...OTHERWISE VFR CONDITIONS
SHOULD HOLD FIRM. THERE ARE MVFR CEILINGS ACROSS NORTHERN LOWER
MICHIGAN...BUT EVEN THESE CLOUDS SHOULD LIFT BEFORE THEY STREAM
INTO THE TAF SITES. SO...VFR THROUGH 18Z THURSDAY. THE CLOUDS
SHOULD SCATTER OUT TONIGHT AS DRIER AIR PUSHES IN WITH MAINLY
CLEAR SKIES EXPECTED BY THURSDAY MORNING. SCATTERED CUMULUS CLOUDS
WITH BASES AROUND 4000FT MAY REDEVELOP THURSDAY MORNING.

NORTH WINDS WILL GUST AT TIMES TO 20 KNOTS THROUGH 00Z...AFTER
WHICH TIME AT 5-10 KNOT NORTH WIND SHOULD PREVAIL.

&&

.MARINE...
ISSUED AT 320 AM EDT WED JUL 23 2014

SCA AND BEACH HAZARDS STATEMENT REMAINS IN EFFECT TODAY. WINDS WILL
INCREASE FROM THE NORTH TODAY BEHIND THE COLD FRONT AND WAVES WILL
INCREASE TO 3 TO 5 FEET. LONGSHORE CURRENTS WILL LIKELY DEVELOP
LATER TODAY. NORTH FACING PIERS WILL BE A TARGET AREA FOR STRUCTURAL
CURRENTS AND SWIMMERS WOULD BE WISE TO AVOID THOSE AREAS.


&&

.HYDROLOGY...
ISSUED AT 320 AM EDT WED JUL 23 2014

HYDRO CONCERNS ARE MINIMAL. OVERNIGHT RAINFALL WAS AROUND 1.25
INCHES ALONG THE LAKE SHORE WHICH SHOULDN/T CAUSE HYDRO PROBLEMS.

&&

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

     BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT 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...93
SHORT TERM...93
LONG TERM...WDM
AVIATION...DUKE
HYDROLOGY...93
MARINE...93





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