FXUS63 KMQT 081124 AAA
AFDMQT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
625 AM EST TUE DEC 8 2009
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW LONGWAVE TROUGH EXTENDING
FROM WESTERN HUDSON BAY SOUTHWEST THROUGH MONTANA THE SOUTHWEST TO
THROUGH THE GREAT BASIN. A BROAD WEAK RIDGE IS OVER THE UPPER GREAT
LAKES REGION. A SHORTWAVE STRETCHES FROM NORTHERN MINNESOTA EAST TO
NEW ENGLAND. OTHER WEAK SHORTWAVES ARE BEING EJECTED OUT OF THE BASE
OF THE LONGWAVE AND ARE OVER SOUTHWEST SOUTH DAKOTA AND OVER THE
CENTRAL PLAINS. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER SOUTHERN
SASKATCHEWAN AND ACCOMPANYING RIDGE BLANKETING THE GREAT LAKES
REGION. A DEEP LOW IS DEVELOPING OVER GRAND JUNCTION. A WEAK SURFACE
TOUGH ASSOCIATED WITH MID LEVEL SHORTWAVE STRETCHES FROM NEW ENGLAND
TO WESTERN LAKE SUPERIOR THIS MORNING.
&&
.DISCUSSION...
THE SOUTH END OF THE LONGWAVE TROUGH WILL SWEEP INTO THE CENTRAL
PLAINS WHILE THE NORTH END REMAINS OVER THE NORTHERN HIGH PLAINS AND
CENTRAL CANADA. THIS WILL PUSH THE RIDGE OVER THE FORECAST AREA A
LITTLE NORTH INTO CENTRAL ONTARIO. THE GRAND JUNCTION LOW WILL SHIFT
TO NEAR KANSAS CITY. THE SURFACE RIDGE OVER THE AREA WILL SHIFT TO
NEW ENGLAND. WEAK SHORTWAVES WILL MOVE INTO NORTHERN MINNESOTA AND
OVER CENTRAL MISSISSIPPI RIVER VALLEY. WINDS WILL BE OUT OF THE
NORTHWEST THIS MORNING OVER THE LAKE AND VEERING MORE NORTHEAST. THE
LAKE-850MB DELTA-T'S WILL BE AROUND 18C OVER LAKE SUPERIOR. 925MB
WIND CONVERGENCE WILL BE WEAK. THUS WILL BE CALLING FOR LES DOWNWIND
OF LAKE SUPERIOR. GUIDANCE SHOWING NEARLY SATURATED CONDITIONS WILL
BE THE RULE OVER THE FORECAST AREA IN THE MORNING CONTRIBUTING TO
THE LAKE EFFECT SNOWS.
THE LONGWAVE TROUGH WILL MOVE TO THE WESTERN DAKOTAS WHILE THE
SOUTHERN PART OF THE TROUGH WILL BECOME A CLOSED LOW OVER SOUTHERN
WISCONSIN TONIGHT. SHORTWAVES SHIFTING OUT OF THE BASE OF THIS LOW
WILL SPREAD INTO THE FORECAST AREA LATE. THE SURFACE LOW WILL MOVE
INTO SOUTHERN LAKE MICHIGAN. CYCLONIC FLOW ACROSS THE FORECAST AREA
WILL KEEP A EASTERLY FLOW ACROSS THE FORECAST AREA. DELTA-T'S WILL
BE BETWEEN 13C AND 17C OVER LAKE SUPERIOR. DEEP MOISTURE WILL BE THE
RULE OVER THE UPPER GREAT LAKES REGION. LOW LEVEL CONVERGENCE WILL
BE PARTICULARLY STRONG OVER LAKE SUPERIOR CONTRIBUTING TO MORE LES
DOWNWIND OF LAKE SUPERIOR. THE PRESSURE GRADIENTS WILL BE FAIRLY
TIGHT CONTRIBUTING TO CONSIDERABLE BLOWING SNOW AS WELL. SO LES WITH
STRONG WINDS ARE APT TO PRODUCE OCCASIONAL WHITE OUT CONDITIONS OVER
MUCH OF THE AREA CALLING FOR A WINTER STORM.
THE LONGWAVE TROUGH WILL MOVE INTO CENTRAL CANADA AND EXPAND OVER
THE NORTHERN PLAINS ON WEDNESDAY. A PRONOUNCED SHORTWAVE TROUGH
MOVING THROUGH THE BASE OF THE LONGWAVE WILL SWEEP THROUGH THE UPPER
GREAT LAKES AS IT WEAKENS. THE DEEP LOW WILL MOVE TO CENTRAL LAKE
HURON. DEEP MOISTURE WRAPPING AROUND THIS LOW WILL BLANKET THE GREAT
LAKES REGION. THE TIGHT GRADIENTS POINT TO STRONG WINDS...WHICH WILL
VEER NORTH OF THE WESTERN LAKE SUPERIOR AND STILL NORTHEAST OVER THE
EAST PART OF THE LAKE. A -22C 850MB THERMAL TROUGH WILL SHIFT INTO
WESTERN ONTARIO AND THE UPPER MISSISSIPPI RIVER VALLEY. DELTA-T'S
WILL CONTINUE TO BE COLD ENOUGH TO KEEP LAKE EFFECT SNOWS GOING.
THUS WILL KEEP LES GOING.
THE LONGWAVE WILL MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY AND
CENTRAL CANADA WEDNESDAY NIGHT. A SHORTWAVE WILL SWING THROUGH THE
BASE OF THIS TROUGH AND THROUGH THE FORECAST AREA. DEEP MOISTURE
WRAPPING AROUND THE LOW WILL REMAIN OVER THE FORECAST AREA. THE
SURFACE LOW WILL LIFT NORTHEAST INTO QUEBEC KEEPING A NORTHERLY FLOW
AROUND THE FORECAST AREA. THE 850MB THERMAL TROUGH EDGE EVER CLOSER
TO UPPER MICHIGAN CAUSING THE DELTA-T'S TO INCREASE TO 24C. LOW
LEVEL MOISTURE WILL CONTINUE OVER THE FORECAST AREA. TOGETHER THIS
SHOULD KEEP LAKE EFFECT SNOWS GOING.
THE LONGWAVE TROUGH WILL BECOME ELONGATED AGAIN ON THURSDAY. THIS
TIME IT WILL STRETCH FROM A LOW OVER NORTHERN SASKATCHEWAN ACROSS
NORTHERN ONTARIO...AND CENTRAL QUEBEC. WEAK SHORTWAVES WILL SWEEP
THROUGH THE BASE OF THIS TROUGH AND THROUGH THE FORECAST AREA. THE
SURFACE LOW WILL MOVE TO EAST CENTRAL QUEBEC CAUSING THE GRADIENTS
TO WEAKEN AND WINDS TO DIE DOWN A BIT. WINDS WILL BE LIGHT OUT OF
THE NORTH. A LARGE HIGH WILL DOMINATE THE THE CENTRAL PLAINS AND THE
SOUTHERN STATES. THE 850MB THERMAL TROUGH OF -24C WILL SLIDE INTO
WESTERN LAKE SUPERIOR. COLD AIR WILL REMAIN EMBEDDED OVER THE AREA.
THEREFORE...HIGH TEMPERATURES SHOULD REACH ONLY INTO THE SINGLE
DIGITS...WHILE OVER THE EAST TEMPERATURES COULD REACH 20C.
THEREFORE...WILL BE LOOKING FOR LES AGAIN.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
AT KCMX...EXPECT CONDITIONS TO VARY BTWN MVFR AND IFR WITH LAKE
EFFECT THIS MORNING AS IS THE NATURE OF LAKE EFFECT SHSN...CIGS/VIS
WILL LIKELY STILL BE MORE VARIABLE THAN REFLECTED IN THIS FCST AS
BANDS TRANSIT THE AREA. WEAK HIGH PRES RIDGING WILL SHIFT ACROSS THE
AREA LATER IN THE MORNING/EARLY AFTN...THEN WINDS WILL BECOME ERLY
AS LOW PRES BEGINS STRENGTHENING OVER THE SRN PLAINS. SHOULD SEE
-SHSN BECOME DISORGANIZED DURING THIS TIME...ALLOWING VIS TO IMPROVE
TO VFR WHILE CIGS REMAIN MVFR. EXPECT DETERIORATING CONDITIONS TO
VLIFR DURING THE LATE EVENING AS RAPIDLY DEEPENING LOW PRES MOVES NE
TOWARD THE GREAT LAKES... SPREADING SNOW INTO THE AREA.
AT KSAW...LIGHT DOWNSLOPING WRLY WINDS WILL ALLOW VFR CONDITIONS TO
DOMINATE THRU THE MORNING. VFR CONDITIONS SHOULD THEN LINGER THRU
THE AFTN UNDER INCREASING/THICKENING MID/HIGH CLOUDS AHEAD OF
STRENGTHENING LOW PRES OVER THE SRN PLAINS. EXPECT DETERIORATING
CONDITIONS IN THE EVENING TO VLIFR AS RAPIDLY DEEPENING LOW PRES
MOVES NE TOWARD THE GREAT LAKES...SPREADING SNOW INTO THE AREA.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
BIG STORM AND STRONG WINDS WILL CONTINUE TO BE THE PROBLEM FOR THIS
FORECAST. UPGRADED THE GALE WATCH TO A GALE WARNING EVERYWHERE.
STRONGEST WINDS APPEAR TO BE AHEAD OF THE LOW PRESSURE SYSTEM
TONIGHT THROUGH WED AND THEN AFTER LOW PASSES...WINDS DIE DOWN A
BIT. THIS WILL BE THE FIRST GALE EVENT. SECOND GALE EVENT WITH WINDS
A BIT LESS THAN WED WILL BEGIN ON THU WITH GALES FOR THE EASTERN TWO
THIRDS THU AFTERNOON THROUGH FRI. A THIRD GALE EVENT WOULD BE
POSSIBLE IF THE GFS VERIFIES FOR SAT. WILL HAVE TO WATCH THAT EVENT
TOO AS PRESSURE GRADIENT GETS TIGHT AGAIN WITH THAT. ADDED PLENTY OF
FREEZING SPRAY TO THE FORECAST...AS TEMPERATURES STAY NEAR OR BELOW
20F THROUGH THE PERIOD. PUT OUT A LAKESHORE FLOOD STATEMENT FOR
ALGER AND MARQUETTE COUNTIES AS WAVES GET UP TO 17 TO 22 FEET WHICH
SHOULD CAUSE SOME MINOR FLOODING OF LOW LYING ROADS NEAR LAKE
SUPERIOR AND SOME BEACH EROSION AS WELL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 1
AM EST /MIDNIGHT CST/ THURSDAY FOR MIZ001>005-009>014-084.
WINTER STORM WARNING FROM 1 AM WEDNESDAY TO 1 AM EST THURSDAY
FOR MIZ006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR
MIZ002-003.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM WED TO 1 AM THU FOR LSZ243>245-263>267.
GALE WARNING FROM 7 AM EST/ 6 AM CST/ TO 7 PM EST / 6 PM CST/ WED
FOR LSZ240>242-246>251.
GALE WARNING FROM 1 AM EST / MIDNIGHT CST/ TO 7 PM EST/ 6 PM CST.
WED FOR LSZ162.
LAKE MICHIGAN...
GALE WARNING FROM 1 AM WED TO 1 AM THU FOR LMZ221-248-250.
&&
$$
SYNOPSIS/DISCUSSION...DLG
AVIATION...07
MARINE...007
