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 260810 AFDGRR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 410 AM EDT SUN OCT 26 2008 LATEST UPDATE...ALL SECTIONS EXCEPT AVIATION... .SYNOPSIS...(425 AM EDT SUN OCT 26 2008) A COLD FRONT WILL PUSH ACROSS THE REGION THIS MORNING BRINGING WINDY CONDITIONS...FALLING AFTERNOON TEMPERATURES AND SCATTERED SHOWERS. A SECOND COLD FRONT WILL PLOW INTO THE AREA LATE TONIGHT WITH EVEN COLDER AIR. SOME AREAS MAY SEE A RAIN AND SNOW MIX TONIGHT...BUT ALL AREAS IN SOUTHWEST LOWER MICHIGAN WILL SEE SNOW BY MONDAY AS THE COLDEST AIR OF THE SEASON ARRIVES. LIGHT SNOW ACCUMULATIONS ON GRASSY AREAS WILL BE POSSIBLE MONDAY THROUGH TUESDAY. && .SHORT TERM...(425 AM EDT SUN OCT 26 2008) (TODAY THROUGH TUESDAY) WILL TWEAK THE FORECAST SOMEWHAT THIS MORNING...MAINLY DEALING WITH PCPN TYPE. THE COLDEST AIR DOES NOT ARRIVE UNTIL MONDAY WITH A SECONDARY COLD FRONT. UNTIL THEN THE BULK OF THE PCPN WILL REMAIN RAIN. WILL MAINTAIN WIND HEADLINES AS IS...ALTHOUGH WITH THE FRONT MOVING IN A BIT SLOWER IT APPEARS THE STRONGEST WINDS WILL NOT ARRIVE UNTIL AFTERNOON. HAVE TRIMMED BACK A LITTLE ON THE SPEEDS TOO...AS INLAND AREAS SHOULD OCCASIONALLY SEE AFTERNOON GUSTS AROUND 45 MPH...AND AROUND 50 MPH ALONG THE LAKE SHORE. A BAND OF LIGHT SHOWERS WERE LIFTING THROUGH THE CWA THIS MORNING WITH THE FIRST COLD FRONT. THERE WAS SOME SURFACE BASED INSTABILITY...SO WILL MAINTAIN THE MENTION OF THUNDER. WE MAY SEE A QUICK BURST OF LAKE EFFECT RAIN SHOWERS BEHIND THE FRONT. THEN SOMEWHAT DRIER AIR WILL MOVE INTO THE REGION SOUTH OF I96 WHERE SOME AFTERNOON SUNSHINE WILL BE POSSIBLE. HOWEVER...TO THE NORTH THE STRONGER SECONDARY FRONT WILL BE APPROACHING AND RAIN SHOWERS WILL INCREASE BY LATE DAY ACROSS CENTRAL LOWER. A CORE OF COLDER H8 TEMPS THAT WAS NEAR LAKE WINNIPEG THIS MORNING WILL PIVOT SOUTHEAST AHEAD OF THE SECOND FRONT AND SHOULD CLIP SOUTHERN LOWER. THIS WILL RESULT IN THE SOUTH SEEING A BETTER CHANCE OF A RAIN/SNOW MIX TONIGHT THEN THE NORTHERN CWA. ALL IN ALL...FEEL HIGHLY CONFIDENT THAT THERE WILL BE A FAIRLY SOLID BAND OF SHOWERS WITH THIS FRONT AND WILL CARRY HIGH POPS FOR LATE TONIGHT ACROSS THE CWA. THE REAL COLD AIR ARRIVES BEHIND THE SECOND FRONT ON MONDAY AND HOLDS OVER LOWER MICHIGAN INTO TUESDAY. ALL AREAS WILL SEE ANY RAIN CHANGE OVER TO SNOW FROM WEST TO EAST THROUGH THE DAY ON MONDAY. THE LAKE EFFECT SHOULD ALSO BE GOING STRONG THROUGH THIS PERIOD AS WE MAINTAIN CYCLONIC FLOW...H8 TEMPS OF -8 TO -10C AND DEEP MOISTURE. RIGHT NOW THE THINKING IS THAT MOST AREAS WILL SEE AT LEAST A LIGHT DUSTING OF SNOW THROUGH THIS PERIOD...WITH LOCALIZED 2-3 INCHES POSSIBLE IF A PERSISTENT LAKE EFFECT BAND IS ESTABLISHED. OVERALL NOTHING TOO SEVERE...BUT A TASTE OF WINTER FOR SURE. && .LONG TERM...(425 AM EDT SUN OCT 26 2008) (TUESDAY NIGHT THROUGH SATURDAY) SFC RIDGING BUILDING IN AT THE BEGINNING OF THE PERIOD ALONG WITH HEIGHT RISES AS UPPER TROUGH MOVES EAST. THIS WILL MEAN FAIR WEATHER WITH MODERATING TEMPERATURES FOR WEDNESDAY THROUGH FRIDAY. THE ONLY POTENTIAL FORECAST ISSUE IS THE TIMING OF A SHORTWAVE TROUGH AND COLD FROPA AND THE RESULTING PRECIPITATION CHANCES TOWARDS THE END OF THE PERIOD. THE 00Z ECMWF IS ABOUT 24 HOURS SLOWER THAN THE 00Z GFS WITH THE FROPA. POPS MAY BE NEEDED FOR EITHER FRIDAY OR SATURDAY DEPENDING ON WHICH MODEL VERIFIES. LEFT THINGS DRY FOR NOW PENDING BETTER MODEL AGREEMENT. && .MARINE...(425 AM EDT SUN OCT 26 2008) A GALE WARNING WILL BE CONTINUED TODAY INTO THE FIRST HALF OF MONDAY. WIND FIELDS LOOK SLIGHTLY LESS...THEREFORE WILL CALL FOR 40 KNOT GALES. WAVES WILL EXCEED 10 FEET AT TIMES. && .AVIATION...(1142 PM EDT SAT OCT 25 2008) THE CLEARING OF THE LOW CLOUDS IS PROGRESSING AS EXPECTED AS IS THE SPREADING OF THE MID CLOUDS. RADAR SHOWS ECHOS BUT THIS IS FOR THE MOST PART VIRGA. THE CLEARING OF THE LOW CLOUDS HAS NOT REACHED LAN AND JXN YET (1130 PM) BUT SHOULD REACH THERE AROUND 06Z. DUE TO THE MID LEVEL WARM ADVECTION I DO NOT SEE MUCH IN THE WAY OF LOW CLOUDS OVERNIGHT ONCE THE LOW CLOUDS HAVE MOVED OUT. THE TRUE COLD AIR PUSH DOES NOT REACH THE CWA TILL AROUND 00Z. THUS I HAVE EXPUNGED THE SHOWERS FROM THE TAFS. THE LATEST MODELS SEEM TO SUGGEST TO MUCH LOW LEVEL DRY AIR FOR ANY SIGNIFICANT SHOWERS SUNDAY (ENOUGH TO PUT IN THE TAFS). ONCE THE COLD AIR REACHES THE CWA EARLY SUNDAY NIGHT...WELL THAT IS ANOTHER STORY. THEN NORTHWEST FLOW LAKE EFFECT WILL DEVELOP AND TAF SITES WEST OF US-131 SHOULD SEE SHOWERS AND MVFR CIGS BY 10 AM OR SO. && .HYDROLOGY...(425 AM EDT SUN OCT 26 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 TODAY...ENTIRE CWA. LM...GALE WARNING IN EFFECT ST. JOE TO MANISTEE TODAY THROUGH MONDAY AFTERNOON. && $$ SYNOPSIS: JK SHORT TERM: JK LONG TERM: OSTUNO MARINE: JK AVIATION: WDM HYDROLOGY: JK
