Issued by NWS Grand Rapids, MI
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
000 FXUS63 KGRR 252235 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 635 PM EDT SAT OCT 25 2008 LATEST UPDATE...AVIATION... .SYNOPSIS...(430 PM EDT SAT OCT 25 2008) A STRONG COLD FRONT WILL CROSS SOUTHWEST LOWER MICHIGAN EARLY SUNDAY MORNING AND VERY WINDY CONDITIONS WILL DEVELOP. SCATTERED RAIN SHOWERS WILL BECOME MIXED WITH OR CHANGE TO SNOW SHOWERS SUNDAY NIGHT AS THE COLDEST AIR OF THE SEASON ARRIVES. SOME SLUSHY SNOW ACCUMULATIONS WILL BE POSSIBLE SUNDAY NIGHT AND MONDAY...EXCEPT CLOSE TO THE LAKE MICHIGAN SHORELINE. UNSEASONABLY COLD TEMPERATURES AND SCATTERED LAKE EFFECT RAIN AND SNOW SHOWERS WILL LINGER OVER THE AREA THROUGH TUESDAY BEFORE A MODERATING TREND BEGINS. && .SHORT TERM...(430 PM EDT SAT OCT 25 2008) (TODAY THROUGH MONDAY) WILL GO WITH A DRY FCST THIS EVENING AS H5 UPPER LOW/TROUGH EXITS TO THE NORTHEAST AND WE WAIT FOR THE COLD FRONT TO ARRIVE FROM THE WEST AFTER 06Z. IT WILL BE A POTENT FRONT... DRIVEN BY A 150 KT UPPER LEVEL JET. MODELS SHOW A STRONG VORT MAX ON THE LEFT SIDE OF THE JET (AND SLIGHTLY SUB ZERO LIFTED INDICES) ARRIVING WITH THE FRONT SO WILL HAVE CHANCE POPS RETURNING AFTER 06Z AND EVEN A SLIGHT CHANCE OF THUNDERSTORMS. HAVE EXPANDED THE WIND ADVISORY SUNDAY TO COVER THE ENTIRE CWFA. IT IS SOMEWHAT BORDERLINE FOR THE COUNTIES INLAND FROM LAKE MICHIGAN... BUT WE SHOULD SEE GUSTS REACHING OR EXCEEDING 40 MPH AT TIMES DUE TO DEEPLY MIXED CONDITIONS STILL SHOWN IN THE FCST SOUNDINGS. WILL CARRY LIKELY POPS FOR RAIN SHOWERS/ISOLATED TSTMS IN THE MORNING AS THE COLD FRONT/VORT MAX COMES THROUGH... THEN SCATTERED POPS FOR MIXED RAIN AND SNOW SHOWERS IN THE AFTERNOON AS THE COLD AIR (-4C AT H8) POURS ACROSS THE LAKE. IT/S INTERESTING TO NOTE THAT BUFKIT RH PROFILES STILL SHOW VERY DRY AIR BELOW 5K FEET SUNDAY AFTERNOON AND EVENING... SO LAKE EFFECT PCPN PROBABLY WILL NOT BE TOO SIGNIFICANT. HOWEVER AS THE POLAR JET DIPS SOUTH OF THE STATE AND DEEPER MOISTURE ARRIVES SUNDAY NIGHT... LAKE EFFECT SHOWERS SHOULD INCREASE IN INTENSITY WITH SOME LIGHT/SLUSHY SNOW ACCUMULATIONS POSSIBLE BY DAYBREAK MONDAY. THE BEST CHANCE OF ACCUMULATIONS WILL BE INLAND FROM LAKE MICHIGAN AWAY FROM WARMING INFLUENCE OF WATERS STILL IN THE MID 50S. IN GENERAL TRAVEL PROBABLY WILL NOT BE IMPACTED TOO MUCH SINCE THE GROUND TEMPS ARE STILL VERY WARM.... BUT IF INTENSE SNOW BANDS DO DEVELOP...THE HIGHER SNOWFALL RATES COULD CERTAINLY COAT THE ROADS AND LOWER THE VISIBILITY SIGNIFICANTLY. WINTER WX ADVISORIES MAY BE NEEDED TO COVER THE POTENTIALLY MESSY MONDAY MORNING COMMUTE/FIRST SNOW OF THE SEASON. THE COLD AIR STICKS AROUND MONDAY AND MONDAY NIGHT WITH LAKE EFFECT SNOW SHOWERS CONTINUING. THE PREDOMINATE WIND FLOW IS NW... KEEPING MOST OF THE RAIN/SNOW BANDS ALONG/WEST OF HIGHWAY 131. SOME ACCUMULATIONS ARE CERTAINLY POSSIBLE... PARTICULARLY AT NIGHT AND INLAND FROM THE LAKE. && .LONG TERM...(314 PM EDT SAT OCT 25 2008) (TUESDAY THROUGH SATURDAY) FORECAST CONCERNS ARE FEW DURING THE EXTENDED PERIOD AND MAINLY DEAL WITH PCPN TRENDS TUESDAY. THE DEEP UPPER LOW MOVING THROUGH THE GREAT LAKES WILL BE MOVING INTO NEW ENGLAND BY TUESDAY MORNING. A HIGH AMPLITUDE UPPER RIDGE WILL TAKE ITS PLACE. TEMPS WILL SLOWLY RISE TO THE UPPER 50S BY THE END OF THE WEEK AS THE RIDGE SLIDES EAST. BOTH THE GFS AND ECMWF SHOW A SHORT WAVE UNDERCUTTING THE TROUGH FRIDAY AND MOVING THROUGH THE OHIO VALLEY. THE GFS IS STRONGER AND A LITTLE FARTHER NORTH WITH THIS WAVE THAN THE ECMWF IS. WE/RE NOT GOING TO ADD PCPN TO THE GRIDS AT THIS POINT FOR THIS FEATURE...BUT WILL INCREASE CLOUDS IN THE SW TO ACCOUNT FOR IT. && .MARINE...(430 PM EDT SAT OCT 25 2008) SOUTHWEST WINDS TO 30 KNOTS LATE THIS AFTERNOON AND EVENING WILL PRODUCE WAVES OF 4 FEET OR MORE. GALE FORCE WEST WINDS TO 45 KNOTS ARE EXPECTED TO DEVELOP EARLY SUNDAY MORNING BEHIND THE COLD FRONT... AND REMAIN AT OR ABOVE GALE FORCE INTO MONDAY. && .AVIATION...(635 PM EDT SAT OCT 25 2008) SURGE OF WARMER DRY AIR SFC THROUGH 700 MB ASSOCIATED WITH ANTICYCLONIC RIDGING AHEAD OF THE SHORTWAVE AND ASSOCIATED 140 KNOT 300 MB JET CORE WILL CLEAR OUT THE LOW CLOUDS ACROSS THE AREA BTW 03Z AND 06Z. SKIES ARE CLEARING ACROSS EASTERN WISCONSIN AND SOUTHWEST LAKE MICHIGAN AS I WRITE THIS AROUND 630 PM. THE COLD FRONT COMES THROUGH AROUND 8 AM SUNDAY MORNING AND WILL BE ACCOMPANIED BY SHOWERS AND LOW CIGS WITH GUSTY WINDS. AS THE SECOND SHORTWAVE DIVES INTO THE TROUGH... YET ANOTHER PERIOD OF DRYING WILL HAPPEN SUNDAY AFTERNOON. THIS IS THE RESULT OF SHORTWAVE RIDGE THAT MOVES THROUGH THE AREA DURING SUNDAY AFTERNOON AHEAD OF THE STRONGER SHORTWAVE WHICH COMES THROUGH THE AREA SUNDAY NIGHT. WE STILL SEE DEEP MIXING OF 40 TO 45 KNOTS TO THE GROUND ON GFS AND NAM BUFKIT 15Z THROUGH 21Z SO I PUT HIGHER WINDS IN ALL TAF SITES THAN SHOWN ON MOS. && .HYDROLOGY...(430 PM EDT SAT OCT 25 2008) NO HYDRO CONCERNS AS PCPN NEXT 72 HOURS WILL BE GENERALLY SCATTERED IN NATURE WITH QPF AMOUNTS BELOW HALF INCH. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY SUNDAY...ENTIRE CWFA. LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH LAKE TONIGHT ST JOE TO MANISTEE THEN A GALE WARNING IN EFFECT THROUGH MONDAY AFTERNOON. && $$ SYNOPSIS: MEADE SHORT TERM: MEADE LONG TERM: 93 MARINE: MEADE AVIATION: WDM HYDROLOGY: MEADE
