Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KGRR 042305 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 705 PM EDT TUE AUG 4 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 318 PM EDT TUE AUG 4 2015 ONCE SHOWERS ACROSS INTERIOR PORTIONS OF CENTRAL LOWER DIMINISH BY THIS EVENING...THE AREA IS LOOKING AT A COUPLE OF DRY DAYS AS HIGH PRESSURE MOVES OVER THE AREA. TEMPERATURES WILL BE COMFORTABLE...YET A LITTLE BELOW AVERAGE FOR THIS TIME OF THE YEAR. THE NEXT CHANCE OF RAIN WILL COME IN BEGINNING ON FRIDAY AND LAST INTO THE WEEKEND AS THE NEXT SYSTEM POISED TO AFFECT THE AREA WILL MOVE IN. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 318 PM EDT TUE AUG 4 2015 FCST CHALLENGES/CONCERNS ARE MINIMAL WITH THIS FCST PACKAGE AS THE AREA TENDS TO DRY OUT DURING THE PERIOD WITH HIGH PRESSURE MOVING OVERHEAD. A FEW SPOTTY SHOWERS HAVE DEVELOPED THIS AFTERNOON AS EXPECTED ACROSS THE NE PORTION OF THE CWFA. THIS IS WHERE THE CYCLONIC FLOW ALOFT REMAINS AS OF THIS AFTERNOON. THE SHOWERS WILL DISSIPATE QUICKLY BY EARLY THIS EVENING AS WE LOSE THE HEATING OF THE DAY AND AS THE UPPER JET CORE LIFTS NORTH OF THE AREA. WE ARE EXPECTING NO DIURNAL SHOWERS TO POP ACROSS THE CWFA DURING THE DAY ON WED. THE JET CORE MOVING NORTH AND RIDGING BUILDING IN WILL PROVIDE ENOUGH SUBSIDENCE TO LIMIT VERTICAL GROWTH FOR ANY CUMULUS DEVELOPMENT. TEMPS SHOULD BE CLOSE TO TODAY/S VALUES WITH NOT MUCH CHANGE IN H850 VALUES. WE ARE CONTINUING WITH A MAINLY DRY FCST FOR WED NIGHT THROUGH THU. THE MODEL CONSENSUS YESTERDAY OF KEEPING THE NRN AND SRN STREAMS UNPHASED IS NOW BEING ADVERTISED BY ALL OF THE MODELS. THIS WILL KEEP LOWER MICHIGAN DRY IN BETWEEN BOTH SYSTEMS. TEMPS WILL MODERATE SLIGHTLY WITH MORE LOCATIONS SEEING TEMPS IN THE LOWER 80S. IT LOOKS LIKE THE NEXT CHC OF RAIN WITH THE NEXT SYSTEM WILL COME IN BEYOND THE SHORT TERM PERIOD. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 318 PM EDT TUE AUG 4 2015 UPCOMING WEEKEND LOOKS FAIR WITH A CHANCE OF SHOWERS AT ABOUT ANYTIME AND A FEW ISOLATED A STRONG THUNDERSTORMS EITHER OF SATURDAY OR SUNDAY AFTERNOON...BUT NOT SUBSTANTIAL RAINFALL EXPECTED. TEMPERATURES LOOKS SEASONABLE WITH HIGHS AROUND 80 OR BETTER WITH LOWS IN THE MID 60S AS DEWPOINTS SLOWLY INCREASE IN SATURDAY NIGHT. OVERALL PATTERN OF UPPER TROUGH OVER THE EAST WITH AN UPSTREAM RIDGE OVER CENTRAL WEST AND A PACIFIC TROUGH JUST OFF THE WEST COAST WILL CONTINUE ALTHOUGH THE VORTEX OVER HUDSON BAY WEAKENS CONSIDERABLY RESULTING IN A MORE ZONAL FLOW ACROSS THE UPPER MIDWEST. THIS WILL RESULT IN A GRADUAL WARMING TO SEASONAL AUGUST TEMPERATURES AND HUMIDITY. WHILE MEDIUM RANGE GUIDANCE GENERALLY AGREES WITH LARGE SCALE DETAILS...SIGNIFICANT DIFFERENCE DEVELOP EARLY IN THE WEEKEND CONCERNING SHORTWAVE INTERACTIONS AND RESULTING SURFACE FRONTAL POSITIONS. GFS/ECM/FIM ALL SHOW WEAKENING SHORTWAVE MOVING ESE INTO AREA FRIDAY NIGHT WITH WEAK SURFACE WARM FRONT. LIKELY TO SEE REMAINS OF DYING MCS APPROACH ON AREA FRIDAY WITH INCREASING HIGH/MID CLOUDS BUT BEST LIFT STAY NORTH SO JUST A FEW SHOWERS POSSIBLE SUPPORTED BY WAA LIFT AND MOIST FLUX CONVERGENCE ON NOSE OF MODEST WSW LOW LEVEL JET. A SECOND SHORTWAVE APPROACHES ON SUNDAY WITH ECM/FIM TRACK ACROSS MI WITH A BIT OF FRONTOGENESIS A DEVELOPING COLD FRONT BEGINS TO MOVE NORTH TO SOUTH. MODERATE INSTABILITY AND SHEAR COULD SUPPORT SOME ISOLATED STRONG STORMS ALONG AND AHEAD OF THE FRONT SUNDAY. THE GFS HOWEVER IS FURTHER NORTH WITH THIS SHORTWAVE AND INSTEAD ITS SOLUTION HAS A SUBSEQUENT 3RD SHORTWAVE DEVELOP AND PUSH FRONT INTO THE AREA LATE MONDAY INTO TUESDAY. LOOKING FARTHER INTO NEXT WEEK...THE STORY LOOKS SIMILAR WITH CONTINUED DRY WEATHER PATTERN AND ANOTHER SEASONABLY COOL AND DRY CANADIAN AIRMASS AS UPPER TROUGH DEEPENS AGAIN BY MIDWEEK. THAT LOOKS TO BE FOLLOWED BY ANOTHER SHOT OF WARM AIR AND POTENTIAL WET WEATHER AS PERHAPS SOME STRONGER PACIFIC SHORTWAVES CRASH THE WESTERN RIDGE...RESULTING IN A MORE PROGRESSIVE PATTERN. THIS WILL ALL DEPEND SOMEWHAT ON THE PURGES OF SEVERAL TROPICAL PACIFIC SYSTEMS AND THEIR INTERACTION WITH WESTERLIES. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 704 PM EDT TUE AUG 4 2015 SCT/BKN CU WILL DISSIPATE WITH SUNSET AS WILL THE WIND. SOME HIGH CLOUDS ARE POSSIBLE OVER THE SRN TAF SITES. VFR EXPECTED THROUGH THE PERIOD. && .MARINE... ISSUED AT 318 PM EDT TUE AUG 4 2015 LINGERING SLIGHTLY GUSTY WINDS AND WAVES OF 1 TO 3 FEET WILL DIMINISH THIS EVENING AND TONIGHT AS HIGH PRESSURE BUILDS OVERHEAD AND THE GRADIENT BECOMES LIGHT. WE SHOULD SEE WINDS GENERALLY REMAIN AT OR BELOW 15 KNOTS THEN THROUGH THE REMAINDER OF THE WORK WEEK. THE FLOW WILL BECOME OFFSHORE BY THU...SO WATER TEMPERATURES WILL LIKELY DROP A BIT WITH UPWELLING POTENTIALLY OCCURRING. && .HYDROLOGY... ISSUED AT 1233 PM EDT TUE AUG 4 2015 NO FLOODING ISSUES ARE EXPECTED AS A RELATIVELY DRY PATTERN SETS UP OVER LOWER MICHIGAN. SOME SHOWERS WILL BE POSSIBLE OFF AND ON THROUGH THE WEEKEND...BUT NO SIGNIFICANT RAINFALL EVENTS ARE EXPECTED AT THIS TIME. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...COBB AVIATION...04 HYDROLOGY...MACZKO MARINE...NJJ

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.