Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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000 FXUS63 KGRR 040512 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 112 AM EDT SAT JUL 4 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 306 PM EDT FRI JUL 3 2015 THE AREA WILL SEE VERY QUIET AND SUMMER-LIKE TEMPERATURES FOR THE FOURTH OF JULY HOLIDAY WEEKEND. THE ONLY CHANCE OF RAIN THROUGH THE WEEKEND WILL BE A SLIGHT CHANCE ACROSS THE INTERIOR PORTIONS OF CENTRAL LOWER MICHIGAN DURING THE AFTERNOON ON INDEPENDENCE DAY. A BETTER CHANCE OF RAIN ACROSS THE AREA WILL ARRIVE LATE MONDAY AND INTO EARLY TUESDAY AS A COLD FRONT MOVES THROUGH THE AREA. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY AT THAT TIME. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 306 PM EDT FRI JUL 3 2015 FORECAST CHALLENGES REMAIN FAIRLY MINIMAL THROUGH THE SHORT TERM FOR THE AREA ONCE AGAIN. THE ONLY THING OF NOTE REMAINS THE LOW CHANCE OF A SHOWER OR STORM FOR SAT. THE ONLY THING AROUND THE AREA THIS AFTERNOON ARE SOME HIGH CLOUDS FLOATING THROUGH ACROSS THE SOUTH...AND A GOOD DEAL OF SMOKE IN THE UPPER LEVELS OF THE ATMOSPHERE FROM THE FIRES ACROSS CENTRAL CANADA. HIGH PRESSURE IS KEEPING THE ATMOSPHERE VERY DRY AT THIS TIME WITH A SUBSIDENCE INVERSION CAPPING ANY DIURNAL CLOUDS TRYING TO FORM. WE HAVE MAINTAINED THE LOW CHC OF A SHOWER AND STORM FOR INTERIOR SECTIONS OF CENTRAL LOWER MICHIGAN FOR THE DAY ON SATURDAY. MODELS REMAIN CONSISTENT WITH BRING A WEAKENING COLD FRONT INTO THE AREA ON SAT. NOT MUCH MOISTURE RETURN AHEAD OF THE FRONT ASIDE FROM SOME POOLING OF LOW LEVEL MOISTURE POOLING RIGHT ALONG THE FRONT. CAPES OF A FEW HUNDRED J/KG AT BEST ALONG WITH A COUPLE OF INVERSIONS ALOFT WILL LIMIT THE POTENTIAL. THE BEST CHC OF STORMS WILL BE FURTHER NORTH ACROSS NRN LOWER AND ERN UPPER CLOSER TO THE UPPER WAVE. QUIET WEATHER LOOKS TO REMAIN THEN FOR SAT NIGHT THROUGH SUN NIGHT WITH ONLY INCREASING TEMPERATURES DURING THAT PERIOD. HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE AREA IN THE WAKE OF THE SHORT WAVE/FRONT MOVING THROUGH THE REGION ON SAT. A BIT MORE OF A LONG WAVE RIDGE WILL BUILD TOWARD THE REGION AT THAT TIME. TEMPS SHOULD BE WELL INTO THE 80S ON SUN WITH H850 TEMPS IN THE MID TEENS C. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 306 PM EDT FRI JUL 3 2015 WE EXPECT A RELATIVELY NARROW BAND OF SHOWERS AND THUNDERSTORMS TO PASS THROUGH THE AREA LATE MONDAY NIGHT/EARLY TUESDAY MORNING AHEAD OF A COLD FRONT AND SHARP UPPER TROUGH. CONFIDENCE IN TIMING HAS GROWN DUE TO BETTER AGREEMENT BETWEEN THE ECMWF AND GFS. THE SEVERE THREAT IS LIMITED WITH THIS OCCURRING NEAR THE DIURNAL MINIMUM FOR INSTABILITY. DYNAMICS OVERALL DO NOT LOOK FAVORABLE EITHER. WHILE AN IMPRESSIVE LOW LEVEL JET /50+ KT AT 850 MB/ DEVELOPS AHEAD OF THE FRONT...OUR AREA REMAINS SOUTH OF THE SPEED MAXIMUM AND WELL SOUTH OF THE ENTRANCE REGION OF THE ASSOCIATED UPPER JET. THERE IS ALMOST NO LOW LEVEL SHEAR COMPONENT EXPECTED NORMAL TO THE FRONT...SO A FAIRLY UNIFORM BAND OF SHOWERS AND THUNDERSTORMS SHOULD BE THE RESULT. THE UPPER TROUGH ITSELF IS CHARACTERIZED BY CONFLUENT FLOW DOWNSTREAM OF THE AXIS SUGGESTING GENERAL WEAKENING. WE ARE MORE CONCERNED ABOUT NUISANCE FLOODING AS IMPRESSIVE PRECIPITABLE WATER AND STRONG MOISTURE TRANSPORT WILL BOOST PRECIPITATION EFFICIENCY. HOWEVER...A WIDESPREAD FLOODING THREAT IS NOT EXPECTED SINCE PRECIPITATION SHOULD MOVE RATHER QUICKLY THROUGH THE AREA. NO OTHER WEATHER OF SIGNIFICANCE IS EXPECTED AFTER THIS. TEMPERATURES SHOULD REMAIN SLIGHTLY BELOW NORMAL WITH A CHANCE FOR SHOWERS AND THUNDERSTORMS RETURNING TO THE SOUTHERN FORECAST AREA TOWARDS THE END OF THE WORK WEEK. && .AVIATION...
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(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 112 AM EDT SAT JUL 4 2015 VFR CONDITIONS WILL CONTINUE THROUGH THE NEXT 24 HOURS ALONG WITH A LIGHT WESTERLY WIND. THERE COULD BE SOME VERY PATCHY LIGHT FOG TOWARD MORNING...BUT IT IS NOT EXPECTED TO BECOME ANY WORSE THE MVFR.
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&& .MARINE... ISSUED AT 306 PM EDT FRI JUL 3 2015 WE DO NOT ANTICIPATE ANY MARINE HEADLINES BEING NEEDED AT THIS TIME THROUGH SUNDAY NIGHT. HIGH PRESSURE WILL GENERALLY BE IN CONTROL FOR MOST OF THE PERIOD ALLOWING FOR A WEAK GRADIENT TO REMAIN IN PLACE. WINDS SHOULD REMAIN BELOW 15 KNOTS THROUGH THE HOLIDAY WEEKEND. WINDS WILL BEGIN TO INCREASE SUNDAY NIGHT...WITH SMALL CRAFT ADVISORY WINDS POSSIBLE LATE MONDAY AHEAD OF A COLD FRONT. && .HYDROLOGY... ISSUED AT 1136 AM EDT FRI JUL 3 2015 SIGNIFICANT IMPROVEMENT CONTINUES ON AREA RIVERS. THE LONE ADVISORY AT HOLT ON THE SYCAMORE CREEK IS EXPECTED TO RECEDE BELOW ITS BANKS WITHIN THE NEXT 24 HOURS OR SO. THERE IS MINIMAL THREAT FOR RAINFALL OVER THE NEXT FEW DAYS. ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE THROUGH PORTIONS OF CENTRAL LOWER MICHIGAN SATURDAY AFTERNOON WITH VERY BRIEF AND LOCALIZED DOWNPOURS POSSIBLE. OTHERWISE...DRY WEATHER WILL CONTINUE THROUGH THE NEXT THREE DAYS AND THROUGH THE MAJORITY OF MONDAY. A COLD FRONT WILL BRING IN THE NEXT ROUND OF RAIN LATE MONDAY EVENING. EXPECTED AMOUNTS ARE RATHER TYPICAL OF SUMMER CONVECTION WITH POCKETS OF HEAVIER RAINFALL POSSIBLE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...TJT AVIATION...JK HYDROLOGY...JAM MARINE...NJJ

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