1159 AM CDT
LATE THIS AFTERNOON THROUGH SUN NIGHT...
UPPER LOW OVER QUEBEC AT MIDDAY WILL CONTINUE TO MOVE NE AND ACROSS
LABRADOR TONIGHT. AS IT DOES THE UPPER TROUGH TRAILING SW ACROSS THE
CENTRAL GREAT LAKES WILL CONTINUE OFF TO THE E WHILE AN UPSTREAM
SHORT WAVE MOVES FROM SOUTHERN MANITOBA AND THE NORTHERN PLAINS
EASTWARD...REACHING WESTERN QUEBEC AND THE UPPER MIDWEST BY 12Z SAT.
THIS SYSTEM WILL BE MOISTURE STARVED WITH ONLY AN INCREASE IN HIGH
AND SOME MID LEVEL CLOUDINESS OCCURRING OVERNIGHT WHICH WILL LIMIT
PROSPECTS OF FROST TO THE SE QUARTER OF THE FORECAST AREA AS CLOUDS
ARE NOT EXPECTED TO ARRIVE THERE TIL THE PREDAWN HOURS.
THIS SHORT WAVE PUSHES A WEAK COLD FRONT ACROSS THE NORTHERN AND
WESTERN PORTIONS OF THE LOCAL AREA DURING SAT AFTERNOON AND NIGHT
BUT WITH MINIMAL SHALLOW COLD AIR ADVECTION. THIS ALONG WITH THE
TIMING OF THE FRONT NOT UNTIL AFTERNOON AT THE EARLIEST TEMPERATURES
FOR SAT SHOULD BE ABLE TO REACH THE LOWER AND MID 60S.
WARM AIR ADVECTION TO BE OCCURRING FROM THE CENTRAL PLAINS TO THE
UPPER MIDWEST AND MS VALLEY SAT NIGHT INTO SUN AHEAD OF THE STRONGER
SHORT WAVE...CURRENTLY JUST REACHING SE AK AND THE B.C. COAST AT
MIDDAY...AS IT MOVES ACROSS S CENTRAL CANADA AND THE NORTHERN
PLAINS. WITH 850HPA TEMPS AVERAGING AROUND 7C DURING SUN AFTERNOON
SO THE MID AND UPPER 60S FROM MOS LOOK ON TRACK. THE SHORT WAVE
TROUGH CONTINUES E OVER THE WESTERN GREAT LAKES SUN EVENING
DRAGGING ANOTHER COLD FRONT...THIS ONE A BIT STRONGER...E ACROSS
THE FORECAST AREA BY MON MORNING. MOISTURE REMAINS LIMITED AND
WITH STRONGER DYNAMICS INCLUDING LEFT EXIT REGION OF UPPER JET
MOVING OVER MN AND WI HAVE ONLY SLIGHT CHANCE POPS SUN AFTERNOON
WITH THIS SYSTEM.
SUN NIGHT THROUGH FRI...
SLIGHT CHANCE OF SHOWERS TO LINGER OVER THE LOCAL FORECAST AREA
INTO SUN NIGHT UNTIL THE STORM SYSTEM OVER QUEBEC MOVES FARTHER E
AND THE TRAILING COLD FRONT SAG S THROUGH THE FORECAST AREA. MON
EXPECTED TO BE DRY AS BROAD RIDGING ALOFT MOVES OVER THE REGION
BETWEEN AN UPPER LOW OVER SOUTHERN HUDSON BAY AND THE POSITIVE
TILT TROUGH MOVING ACROSS WESTERN N AMERICA.
AS THE UPPER TROUGH AXIS CONTINUES E TUE ALONG A WESTERN ONTARIO
TO SOUTHERN HIGH PLAINS LINE BY EVENING THE ASSOCIATED SURFACE LOW
WILL BE EJECTING NE FROM THE CENTRAL PLAINS. MODELS SHOWING
RATHER SIGNIFICANT VARIATIONS IN PLACEMENT OF THE SURFACE LOW AT
00Z WED...RANGING FROM CENTRAL IL TO CENTRAL WI...OR ABOUT 300 MI
N TO S. TRACK OF THE LOW OBVIOUSLY WILL HAVE CRITICAL ROLE IN
TEMPERATURES AND RAIN CHANCES. FOR NOW WILL FIGURE ON A TRACK
ALONG OR NEAR THE IL-WI BORDER. SURFACE LOW CONTINUES
NORTHEASTWARD INTO THE CENTRAL GREAT LAKES TUE NIGHT BUT THE UPPER
TROUGH AXIS DOES NOT MOVE E OF THE FORECAST AREA UNTIL THU
AFTERNOON SO HAVE SLIGHT CHANCE POP NUMBERS TIL THE PASSAGE OF THE
UPPER TROUGH. ANOTHER UPPER TROUGH MOVES OVER THE AREA FRI BUT
LOOKS TO BE MOISTURE DEPRIVED FOR THE MOST PART.
AFTER BEING MILD FOR THE SEASON THROUGH THE WEEKEND INTO EARLY
NEXT WEEK TEMPERATURES GO WELL BELOW NORMAL MID AND LATE NEXT
WEEK AS MID AND UPPER FLOW TURNS TO NORTHWESTERLY AND ADVECTS
COLD AIR FROM CENTRAL CANADA ACROSS THE REGION. WITH THE UPPER
TROUGH SHARPENING OVER THE GREAT LAKES...OH VALLEY...LOWER MS
VALLEY AND THE SOUTHEASTERN STATES THU AND FRI THE COLD ARE WILL
BE PULLED FARTHER S ACROSS THE CENTRAL AND EASTERN U.S.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NONE
IZZI
//DISCUSSION...UPDATED 06Z...
WEATHER NIL.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...SLIGHT CHC SHRA.
MONDAY...VFR.
TUESDAY...CHC SHRA AND TSRA.
WEDNESDAY...SLT CHC SHRA.
THURSDAY...SLT CHC SHRA.
KJB
&&
.MARINE...
245 AM CDT
WEAK TROUGH WILL SWEEP ACROSS THE LAKE THIS AFTERNOON BUT WITHOUT
MUCH FANFARE. SOUTHERLY WINDS WILL INCREASE SUNDAY AS THE GRADIENT
TIGHTENS IN ADVANCE OF A LOW TRACKING NORTH OF LAKE SUPERIOR.
FAIRLY WARM AIR BEING ADVECTED NORTH WILL RESULT IN SOMEWHAT
MARINE BOUNDARY LAYER...ESPECIALLY SOUTHERN PORTIONS OF THE LAKE.
STILL ANTICIPATE WINDS GUSTING WELL INTO THE 20 KT RANGE SUNDAY
AFTERNOON OVER NORTHERN PORTIONS OF THE LAKE BEFORE FRONT MOVES
THROUGH WITH A BRIEF PERIOD OF FRESH NORTHWEST WINDS MONDAY.
WINDS SUBSIDE FOR A TIME MONDAY NIGHT BEFORE THE NEXT STORM
APPROACHES THE REGION TUESDAY AND WEDNESDAY. STILL SIGNIFICANT
DIFFERENCES IN THE MODELS WITH REGARDS TO STRENGTH AND TRACK OF
THIS LOW SO HAVE LOWER THAN AVERAGE CONFIDENCE IN THE TUES/WED
FORECAST...BUT POTENTIAL DOES EXIST FOR FAIRLY STRONG WINDS JUST
THE DIRECTION IS TOUGH TO PINPOINT AT THIS POINT.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ005-ILZ006-ILZ012-ILZ013-ILZ020-ILZ021-
ILZ022-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 8 AM SATURDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 8 AM
SATURDAY.
LM...NONE.
&&
$$
