000
FXUS63 KMQT 071119 AAA
AFDMQT
AREA FORECAST DISCUSSION...UPDATED AVIATION DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
720 AM EDT SUN SEP 7 2008
.DISCUSSION...
THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR
RAIN SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT.
WATER VAPOR IMAGERY AND RUC SHOWING A LONGWAVE TROUGH OVER SOUTH
CENTRAL CANADA AND A RIDGE ALONG THE CANADIAN PACIFIC COAST.
SHORTWAVES SWEEPING THROUGH THE BASE OF THIS TROUGH ARE OVER
SOUTHERN MANITOBA...NORTHERN LOWER MICHIGAN...AND MIDDLE MISSISSIPPI
RIVER VALLEY. SURFACE ANALYSIS DEPICTS A LOW OVER NORTHERN ONTARIO
WITH A COLD FRONT DRAPED SOUTHWEST THROUGH MINNESOTA INTO NEBRASKA.
A HIGH IS PUSHING IN FROM SOUTH CENTRAL CANADA. SHOWERS AND
THUNDERSTORMS HAVE BEEN FIRING OVER IOWA AND SOUTHERN WISCONSIN AND
OVER SOUTHEAST MANITOBA AND NORTHWEST MINNESOTA IN RESPONSE TO THE
SHORTWAVE INSTABILITY. LOW LEVEL MOISTURE AHEAD OF THE FRONTAL
SYSTEM HAVE CONTRIBUTED PATCHY FOG AROUND THE AREA THIS MORNING.
THE SHORTWAVE OVER MANITOBA WILL SWEEP INTO BOUNDARY WATERS AREA OF
NORTHERN MINNESOTA TODAY...WHILE THE SHORTWAVE OVER WISCONSIN WILL
LIFT NORTHEAST THROUGH LOWER MICHIGAN WHILE THE IOWA SHORTWAVE
SHIFTS INTO THE U.P. MEANWHILE...THE COLD FRONT WILL SWEEP INTO
CENTRAL U.P. ISENTROPIC ASCENT ASSOCIATED WITH THE FRONTAL SYSTEM
AND Q-VECTOR CONVERGENCE WITH THE SHORTWAVE ENERGY WILL SLIDE
THROUGH THE AREA TODAY. BISMARCK SOUNDINGS TONIGHT WAS MODERATELY
DRY BELOW 750MB AND NEAR SATURATION ABOVE. FORECAST SOUNDINGS
POINTING TO LOW LEVEL DRY CONDITIONS CONTINUING THROUGH THIS
MORNING. CONDITIONS LOOK FAVORABLE FOR CHANCE OF SHOWERS AND
THUNDERSTORMS TODAY. RADAR ALREADY PICKING UP SOME ISOLATED ACTIVITY
OVER WISCONSIN. THE LOCAL HIGH RESOLUTION MODELS SUPPORT THE CURRENT
TIMING ON THE PRECIPITATION SPREADING INTO THE AREA.
A MID LEVEL WEAK LOW SWEEPING THROUGH THE BASE OF THE LONGWAVE
TROUGH WILL SHIFT TO JUST NORTH OF WAWA TONIGHT DRAWING A WEAK
SHORTWAVE ACROSS THE FORECAST AREA. A WEAK SHORTWAVE ACCOMPANYING
THIS TROUGH WILL SHIFT OVER CENTRAL AND EASTERN U.P. THE COLD FRONT
WILL EASTERN U.P. BY MIDNIGHT. A LIGHT DRIER AIR WILL INVADE THE
AREA FROM THE WEST BEHIND THE FRONT WITH A WEAK SURFACE HIGH.
A LITTLE DEEPER SHORTWAVE SWEEPING THROUGH THE BASE OF THE HUDSON
BAY LOW WILL PASS OVER THE FORECAST AREA ON MONDAY. A SURFACE LOW
WILL LIFT OUT OF THE CENTRAL PLAINS ACROSS SOUTHERN LAKE
MICHIGAN...WHILE THE HIGH BUILDS OVER THE NORTHERN PLAINS AND THE
UPPER MISSISSIPPI RIVER VALLEY. THE ECMWF IS KEEPING DRY AIR OVER
THE FORECAST AREA ON MONDAY WITH THE HIGH SPREADING OVER THE
AREA...WHILE THE GFS IS CONSIDERABLY MOIST IN THE LOW LEVELS. WILL
FAVOR A COMPROMISE BETWEEN THESE TWO. THUS LOOKING FOR SHOWER AND
THUNDERSTORMS REMAINING OVER THE AREA...MAINLY OVER THE SOUTH.
FORECAST SOUNDINGS SHOW THAT AN INVERSION WILL BE OVER THE AREA
AROUND 875MB...AND DRY BELOW 900MB. BY SUNSET THE INVERSION WILL
LIFT TO AROUND 700MB AND THE AIR MASS WILL START TO SATURATE. THE
WET BULB ZERO LEVEL WILL BE AROUND 5.5K FEET BY LATE
AFTERNOON...FAVORING SMALL HAIL DEVELOPMENT.
THE SHORTWAVE WILL FINISHING PASSING OVER THE FORECAST AREA MONDAY
NIGHT. THE SURFACE HIGH WILL EDGE INTO THE FORECAST AREA. THUS PLAN
TO DRY OUT CONDITIONS FOR TUESDAY AND TUESDAY NIGHT. THE NEXT SYSTEM
WILL APPROACH THE AREA LATE ON WEDNESDAY.
&&
.AVIATION (FOR THE 12Z TAF ISSUANCE)...
VFR CONDITIONS EXPECTED AT BOTH SITES THROUGH TODAY. BY LATE IN THE
EVENING...MVFR WITH SOME FOG OR MVFR CIGS WILL FORM DUE TO RAIN AT
BOTH SITES. THINGS SHOULD NOT GET OUT OF HAND AS A WEST WIND IS
DOWNSLOPE AT KSAW. FOG WILL ADVECT IN FROM LAKE SUPERIOR INTO KCMX.
THINK WITH THE STRONGER WINDS...SHOULD NOT GET OUT OF HAND THERE
EITHER.
&&
.MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)...
WINDS WILL PICK UP TODAY AS A COLD FRONT MOVES ACROSS LAKE SUPERIOR
TONIGHT AND WILL INCREASE TO UP TO 30 KNOTS TONIGHT. A LOW WILL FORM
OVER NORTHERN ILLINOIS MONDAY EVENING AND DEEPEN AS IT MOVES INTO
WESTERN QUEBEC ON TUESDAY. LOOK FOR HIGH PRESSURE TO BUILD OVER THE
CENTRAL PLAINS AND MINNESOTA TUESDAY AFTERNOON AND MOVE TO THE
EASTERN GREAT LAKES WEDNESDAY EVENING. A LOW PRESSURE TROUGH...
EXTENDING FROM WESTERN ONTARIO TO THE CENTRAL PLAINS WEDNESDAY
EVENING...WILL CROSS LAKE SUPERIOR THURSDAY. NO GALES FORSEEN
ANYTIME SOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
DISCUSSION...DLG
AVIATION...GM
MARINE...GM
