Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 021706
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
106 PM EDT TUE JUN 2 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 329 AM EDT TUE JUN 2 2015

HIGH PRESSURE WILL GIVE US TWO DAYS OF SUNNY SKIES AND LIGHT
WINDS. AFTERNOON TEMPERATURE ARE EXPECTED TO WARM EACH DAY.
MEANWHILE A CANADIAN COLD FRONT PUSHES THROUGH THE AREA ON
THURSDAY AFTERNOON WITH SCATTERED SHOWERS OVER NORTHERN SECTIONS.
THE FRONT THEN STALLS JUST SOUTH OF THE AREA BY FRIDAY MORNING.
THEN THE FRONT WILL PUSH BACK AS A WARM FRONT LATER FRIDAY. THAT
WILL BRING THE THREAT OF SHOWERS AND A FEW THUNDERSTORMS TO THE
AREA THEN. THERE IS THE TREAT OF A MORE SIGNIFICANT STORM SYSTEM
TO MOVE THROUGH THE AREA FOR SUNDAY.

&&

.UPDATE...
ISSUED AT 716 AM EDT TUE JUN 2 2015

I HAVE CANCELED THE FROST ADVISORY.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 329 AM EDT TUE JUN 2 2015

LITTLE GOING ON THE SHORT TERM TO BE CONCERNED WITH. THE PASSAGE
OF A WEAK COLD FRONT THURSDAY AFTERNOON COULD TRIGGER A FEW
SHOWERS NEAR AND NORTH OF ROUTE 10.

OUT BIG PICTURE VIEW OF THE WEATHER IS WE HAVE SPLIT FOR WITH THE
SOUTHERN STREAM COMING ACROSS THE NORTH PACIFIC OCEAN INTO WESTERN
NORTH AMERICAN. THE NORTHERN STREAM IS MOSTLY NORTH OF 55N WHILE
THE SOUTHERN STREAM IS AROUND 35N OVER THE PACIFIC BUT NEAR TO 45N
OVER MICHIGAN. THAT CREATES UPPER CONVERGENCE WHICH IS GREAT FOR
MOSTLY CLEAR SKIES. HOWEVER THIS IS NOT TO LAST. A VERY LARGE
STORM IS FORECAST BY ALL MODELS TO FORM IN THE GULF OF ALASKAN BY
THURSDAY AND THAT CONSOLIDATES BOTH JET STREAMS. THE RESULTS IN A
ROSSY WAVE PROPAGATION WHICH IN TURN WILL RESULT IN A DEEP TROUGH
OVER EASTERN NORTH AMERICA BY THE MIDDLE OF NEXT WEEK. THE
TRANSITION TO THAT PATTERN WILL BRING WARMER TEMPERATURES AND
CONVECTION LATE THIS WEEK INTO EARLY NEXT WEEK. THAN AS THE UPPER
TROUGH DEEPS COOLER AND DRY WEATHER WILL FOLLOW.

THE FRONT ON THURSDAY IS JUST THE FIRST SIGN OF THIS CHANGE. THE
FRONT WILL BE MOISTURE STAVED AND THERE IS LITTLE IN THE WAY OF
INSTABILITY SO I EXPECT ONLY A FEW SHOWERS OVER OUR NORTHERN CWA
IN THE AFTERNOON.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 329 AM EDT TUE JUN 2 2015

A COLD FRONT WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS LATE
THURSDAY NIGHT AND FRIDAY. A CONSENSUS OF MEDIUM RANGE GUIDANCE
SUGGESTS ONLY WEAK INSTABILITY WILL DEVELOP FRIDAY. 00Z ECMWF
GUIDANCE HAS THE RELATIVELY BETTER CHANCE FOR CONVECTION AS IT
SUGGESTS THAT SB CAPE VALUES COULD POTENTIALLY REACH 1000-1500 J/KG
FRIDAY AFTERNOON NEAR TO MAINLY EAST OF US-131.

A CONSENSUS OF LATEST MEDIUM RANGE GUIDANCE STILL SUGGESTS THAT HIGH
PRESSURE SHOULD BUILD IN BEHIND THAT SYSTEM TO PRODUCE FAIR WX FOR
SATURDAY.

A NORTHERN STREAM LOW PRESSURE SYSTEM WILL BRING ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS ON SUNDAY INTO MONDAY. FAIR WEATHER SHOULD
RETURN BEHIND THAT SYSTEM FOR THE MIDDLE PORTION OF NEXT WEEK.
TEMPERATURES SHOULD AVERAGE RATHER CLOSE TO NORMAL THROUGH THE LONG
RANGE FORECAST PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 103 PM EDT TUE JUN 2 2015

WITH HIGH PRESSURE IN CONTROL THE ATMOSPHERE WILL REMAIN
RELATIVELY DRY...AND THE PRESSURE GRADIENT WEAK. THUS TAFS FOR
SOUTHWEST LOWER MI WILL FEATURE CLEAR SKIES AND LIGHT WINDS. A
WEAK ONSHORE FLOW WILL OCCUR ALONG THE LAKESHORE THIS AFTERNOON.

&&

.MARINE...
ISSUED AT 329 AM EDT TUE JUN 2 2015

HIGH PRESSURE MEANS LIGHT WINDS AND DRY AIR SO GREAT WEATHER LOW
WAVES AND LIGHT WINDS IN OUR NEAR SHORE AREA.


&&

.HYDROLOGY...
ISSUED AT 1128 AM EDT TUE JUN 2 2015

NO IMMEDIATE IMPACTS ARE PENDING ON AREA RIVERS AS DRIER WEATHER
HAS MATERIALIZED AND SHOULD CONTINUE AT LEAST THROUGH MOST OF
THURSDAY. MINOR UPWARD MOVEMENT CAN BE SEEN AT MAPLE RAPIDS AND
JACKSON...BUT MANY OF THE SITES HAVE STABILIZED. I SUSPECT THIS
WILL BE THE CASE WITH BOTH AFOREMENTIONED POINTS AS WELL.

THE NEXT ROUND OF PRECIPITATION IS EXPECTED TO HOLD OFF UNTIL LATE
IN THE WORK WEEK. AMOUNTS AROUND ONE-HALF AN MAY BE A DECENT AREA
WIDE AVERAGE. THIS WILL LEAD TO SMALL UPWARD TRENDS ON RIVERS WHEN
THE TIME COMES. NO FLOODING IS ANTICIPATED AT THIS TIME.

&&

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

$$

UPDATE...WDM
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...JAM
MARINE...WDM


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