Alert archive / Michigan / Frost Advisories in 2007

Frost Advisory 1, NWS Grand Rapids, MI

May 12, 200713 counties in Michigan

NWS Grand Rapids, MI issued this frost advisory at May 12, 2007, 3:10 PM EDT for 13 counties in Michigan. It took effect at May 13, 2007, 12:00 AM EDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
May 12, 2007, 3:10 PM EDT (19:10 UTC)
In effect from
May 13, 2007, 12:00 AM EDT
Expired
May 13, 2007, 7:56 AM EDT
In force
8 hr
Issued by
NWS Grand Rapids, MI

Counties Allegan County, MI, Barry County, MI, Calhoun County, MI, Clinton County, MI, Eaton County, MI, Ingham County, MI, Ionia County, MI, Jackson County, MI, Kalamazoo County, MI, Kent County, MI, Muskegon County, MI, Ottawa County, MI, Van Buren County, MI

The radar

The Grand Rapids radar (KGRR), 32 km from the middle of the area, began a volume at 19:08 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Alpena, MI (KAPX), launched 12:00Z, 7.2 hours before the alert went out and 357 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Alpena, MI at 12:00Z on 2007-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Alpena, MI at 12:00Z on 2007-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -90 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1183 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-90 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this frost advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Grand Rapids, MI wrote its last area forecast discussion before this frost advisory went out at May 11, 3:10 PM EDT, 24 hours earlier.

Area forecast discussion, May 11, 3:10 PM EDT, 24 hours before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
310 PM EDT FRI MAY 11 2007

.SHORT TERM...
A COUPLE OF FORECAST CONCERNS OVER THE SHORT TERM.  CONVECTION THIS
EVENING...FREEZING TEMPS EARLY SUNDAY AM...AND TEMPERATURES ON
SATURDAY...PLUS ELEVATED CONVECTION LATE SUNDAY NIGHT.

THE ATMOSPHERE HAS BECOME UNSTABLE THIS AFTERNOON...WITH LIFTED
INDEX VALUES DOWN TO -1 OR -2 DEG C ALONG AND SOUTH OF A MUSKEGON TO
LANSING LINE.  SOME STABLE AIR WAS ARRIVING INTO AMN AREA FROM
SAGINAW BAY.  THE AXIS OF INSTABILITY WILL SHIFT SOUTH THROUGH THE
REST OF THE AFTERNOON.  SURFACE CONVERGENCE IS MAXIMIZED NEAR
HIGHWAY 131...SO CONVECTION WAS INITIATING JUST EAST OF THIS
REGION.  SO FAR TOPS HAVE RISEN TO ABOUT 16K FT...WHICH IS ABOUT AS
HIGH AS THE WARM LAYER SEEN ON THE 12Z APX SOUNDING.  WILL CONTINUE
TO MONITOR TRENDS THOUGH AS FREEZING LEVELS WERE RELATIVELY LOW AND
SOME DRY AIR ALOFT.  WILL KEEP A THE MENTION OF A LOW POP IN FOR
LATE THIS AFTERNOON.

DECIDED TO GO WITH A FREEZE WATCH ROUGHLY NORTH OF A MUSKEGON TO
LANSING LINE FOR LATER SATURDAY NIGHT AND EARLY SUNDAY MORNING.
HIGH PRESSURE IN NORTHWEST ONTARIO WILL DROP SOUTH INTO LOWER MI
SUNDAY MORNING.  THIS SYSTEM WILL BRING AN UNSEASONABLY COOL AND DRY
AIRMASS TO THE AREA.  WITH LIGHT WINDS AND MOSTLY CLEAR SKIES...MANY
LOCATIONS IN THE FREEZE WATCH AREA SHOULD SEE SUB FREEZING
TEMPERATURES.

TEMPERATURES ON SATURDAY COULD END UP COLDER.  THE LARGE AREA OF 6K
TO 15K FT CLOUDS SEEN IN THE UPPER PLAINS IS ASSOCIATED WITH A 700
MB SHORTWAVE.  THIS FEATURE ARRIVES HERE IN SW LOWER MI LATER
TONIGHT AND SAT AM. MODELS DO SUGGEST THAT THE CLOUDS WITH THIS
FEATURE WILL BREAKUP AS IT MOVES IN.  HOWEVER CONSIDERING THAT THERE
IS RAIN IN PARTS OF THE UPPER PLAINS...SUSPECT WE WILL SEE MORE
CLOUDS THAN FORECASTED BY THE MODELS. IF THIS OCCURS...TEMPERATURES
WILL STRUGGLE TO CLIMB ON SATURDAY.

FINALLY ELEVATED INSTABILITY TRIES TO MOVE IN LATE SUNDAY NIGHT FROM
WI.  GIVEN THE ORIENTATION OF THE 1000 TO 500 MB THICKNESS
LINES...WE COULD SEE THE ELEVATED CONVECTION THAT DEVELOPS IN
WISCONSIN AND NW LOWER MI TRYING TO DROP SOUTH INTO SW LOWER MI.  I
WILL KEEP IT DRY AT THIS POINT FOR SUN NIGHT.  WILL NEED TO MONITOR
THIS POTENTIAL CLOSELY OVER THE NEXT COUPLE OF RUNS.

.LONG TERM...
MEDIUM RANGE GUIDANCE CONTINUES TO INDICATE POTENTIAL FOR A VERY
WARM DAY MONDAY AS 850 MB TEMPS MODERATE TO AROUND 15C AND IN A SSW
FLOW REGIME OUT AHEAD OF THE APPROACHING COLD FRONT. THIS FRONT WILL
TRIGGER CONVECTIVE DEVELOPMENT ACROSS OUR AREA LATE MONDAY THROUGH
MONDAY NIGHT AND INTO TUESDAY. CONVECTION MONDAY NIGHT WILL ALSO BE
AIDED BY A 40-50 KT LLJ.

COOLER AND DRY WX WILL RETURN TO OUR AREA BEHIND THAT COLD FRONT FOR
THE MID TO LATE PORTION OF NEXT WEEK AS HIGH PRESSURE BUILDS IN.
MEDIUM RANGE GUIDANCE AND MEX NUMERICAL GUIDANCE CONTINUES TO
SUGGEST THAT THERE WILL BE POTENTIAL FOR FROST EARLY THURSDAY
MORNING WITH THE SFC HIGH OVERHEAD.

.GRR WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY WHITEHALL TO
MANISTEE THROUGH TONIGHT.  SMALL CRAFT ADVISORY ST.
JOSEPH TO WHITEHALL THROUGH TONIGHT.

FREEZE WATCH NORTH OF A MUSKEGON TO LANSING LINE LATE SAT NIGHT TO
EARLY SUN AM.

&&

MJS LAURENS
Hazardous weather outlook, May 11, 5:15 PM EDT, 21 hours 55 minutes before
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The office that day

Everything else NWS Grand Rapids, MI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 12, 3:10 PM EDTFreeze WarningGRRClare, Gratiot, Isabella, Lake, Mason, Mecosta and 4 more17 hr

Nearby

Frost Advisories in Michigan, 2007Every frost advisory in 2007

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.