332 AM CDT
THE MAIN FORECAST CONCERNS WILL BE THE POTENTIAL FOR FROST ACROSS
MY WESTERN AND SOUTHERN COUNTIES TONIGHT.
SURFACE HIGH PRESSURE CENTERED ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY THIS MORNING IS ALLOWING TEMPERATURES TO DROP NICELY THIS
MORNING ACROSS MY NORTH CENTRAL ILLINOIS COUNTIES. HOWEVER...A
PREVAILING LIGHT NORTHERLY WIND IS KEEPING TEMPERATURES FROM
DROPPING LOWER THEN THE MID TO UPPER 30S. I STILL ANTICIPATE THAT
NORTH CENTRAL ILLINOIS WILL SEE SOME SPOTTY FROST...ESPECIALLY IN
WELL PROTECTED AREAS.
THIS SURFACE HIGH WILL SLOWLY SHIFT SOUTHWARD ACROSS NORTHERN
ILLINOIS LATER TODAY. TEMPERATURES WILL BE UNSEASONABLY COOL UNDER
THIS HIGH TODAY WITH MID TO UPPER 50S LIKELY ACROSS THE REGION.
THESE COOL DAY TIME HIGHS WILL SET THE STAGE FOR LOW TO MID 30S
ACROSS ALL AREAS EXCEPT FOR CHICAGO AND AREAS NEAR THE LAKE TONIGHT
UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS. I AM CONCERNED THAT SOME
AREAS ACROSS NORTH CENTRAL ILLINOIS WILL SEE TEMPERATURES DROP
BELOW 32 TONIGHT. I HAVE UNDERCUT GUIDANCE BY SEVERAL DEGREES
GIVEN THE PROXIMITY OF THE SURFACE HIGH AND THE ANTICIPATION OF
EFFICIENT RADIATIONAL COOLING. HOWEVER...I HAVE OPTED TO HOLD OFF
ON FROST HEADLINES IN ORDER TO LET THE DAY SHIFT GET A BETTER
UNDERSTANDING OF THE EXACT AREAS MOST AT RISK.
A GOOD WARMING TREND WILL BEGIN NEXT WEEK. HOWEVER...IT APPEARS THAT
THIS WARMING TREND MAY BE SOMEWHAT SLOWER THAN PREVIOUS ANTICIPATED.
HURRICANE OPHELIA WILL MOVE NORTH ACROSS THE ATLANTIC OVER THE NEXT
COUPLE OF DAYS AND THIS WILL TEMPORALLY HALT THE PROGRESS OF THE
EAST COAST LOW...AND ALSO THE SURFACE HIGH ACROSS OUR AREA. BECAUSE
OF THIS...TEMPERATURES MAY BE SLOW TO WARM ON SUNDAY IN SPITE OF
THE FACT THAT MID LEVEL TEMPERATURES WILL BE ON THE RISE.
TEMPERATURES MAY ONLY TOP OUT IN THE LOW TO MID 60S DUE TO WEAK
BOUNDARY LAYER WINDS AND POOR MIXING. BECAUSE OF THIS...THE REALLY
NICE TEMPERATURES IN THE 70S MAY NOT GET HERE UNTIL MONDAY.
THE UPPER LEVEL RIDGE WILL BUILD EASTWARD THROUGH MID WEEK...LIKELY
PRODUCING A FEW WARM AND DRY DAYS ACROSS THE AREA. HOWEVER...BY THE
END OF THE PERIOD INTO NEXT WEEKEND...IT APPEARS THAT A LARGE TROUGH
WILL DIG ACROSS THE WESTERN CONUS. THIS COULD RESULT IN AN
ENERGETIC STORM ACROSS THE THE CENTRAL CONUS. HOWEVER...AT THIS
TIME IT APPEARS THAT THE MAIN IMPACTS FROM THIS SYSTEM WILL NOT
AFFECT MY AREA THROUGH THE CURRENT FORECAST PERIOD.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* NW GUSTS UP TO 20 KT WILL DEVELOP BY 16Z AND CONTINUE THROUGH 0Z.
JEE
//DISCUSSION...UPDATED 12Z...
ALL IS QUIET AT THE MOMENT AND HOPING IT WILL STAY THAT WAY
TODAY...AS HIGH PRESSURE MOVES IN FROM THE NW. THE LAKE EFFECT
SHOWER MACHINE HAS TURNED OFF FOR THE TIME BEING. A STRAY SHOWER OR
TWO MAY PASS OVER GYY...BUT DID NOT HAVE ENOUGH CONFIDENCE IN THE
TIMING OR COVERAGE TO PUT ANY MENTION OF PRECIP IN THE GYY TAF. LAKE
EFFECT CLOUD COVER HAS PERSISTED THIS MORNING...WITH SCT TO BKN040
CIGS OCCURRING FOR ORD EASTWARD. THE LAKE EFFECT CLOUD COVER WILL
BE WITH US FOR AT LEAST THE REST OF THIS MORNING. AS THE SURFACE
WARMS LATE THIS MORNING...SCT030 CU WILL DEVELOP AND N WINDS WILL
PICK UP. GUSTS UP TO 20 KT WILL ALSO OCCUR LATE THIS AFTERNOON
THROUGH THIS EVENING. SKIES WILL BEGIN TO SCATTER OUT TO FEW AND
THEN CLEAR THIS EVENING AS WE LOSE THE DAYTIME HEATING.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN WHEN THE LAKE EFFECT CLOUD COVER WILL
DISSIPATE.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH FRIDAY...VFR.
JEE
&&
.MARINE...
304 AM CDT
THE LAKE EFFECT SHOWERS HAVE DIMINISHED GREATLY OVER THE PAST
HOUR...BUT STILL HAVE A SLIGHT CHANCE OF SHOWERS OVER THE SOUTHERN
HALF OF THE LAKE THROUGH 18Z TODAY. WINDS AND WAVES WILL ALSO
BEGIN TO SUBSIDE THROUGHOUT THE DAY TODAY AS THE PRESSURE GRADIENT
RELAXES OVER LAKE MICHIGAN. HIGH PRESSURE MOVES IN FROM THE NORTHWEST
TODAY AND WILL REMAIN OVER THE REGION THROUGH MOST OF NEXT WEEK.
THIS WILL RESULT IN CALMER WINDS COMPARED TO THE PAST FEW
DAYS...AND SMALLER WAVES.
CONCERNING HEADLINES...THE GALE WARNING FOR THE OPEN LAKE MICHIGAN
WATERS AND INDIANA LAKESHORE WAS ALLOWED TO EXPIRE AS WINDS HAVE
DIMINISHED TO BELOW GALE. HOWEVER...A RIP CURRENT STATEMENT AND
SMALL CRAFT ADVISORY ARE STILL IN EFFECT. THE RIP CURRENT
STATEMENT FOR ALL OF THE ILLINOIS AND INDIANA SHORES GOES THROUGH
7 PM TONIGHT AND THE SMALL CRAFT ADVISORY REMAINS IN EFFECT
THROUGH 1AM TONIGHT. NORTH WINDS IN EXCESS OF 25 KT WILL CREATE
WAVES UP TO 14 FT TODAY. THE WIND AND WAVES WILL SLOWLY WEAKEN FOR
THE NEXT FEW DAYS.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 1 AM SUNDAY.
&&
$$
