829 PM CDT
FOR EVENING UPDATE...
NO SIGNIFICANT FORECAST CHANGES NECESSARY.
LIGHT SOUTHEAST WINDS...MILD TEMPERATURES...AND JUST A LITTLE THIN
CIRRUS SPILLING ACROSS THE REGION WILL SET THE STAGE FOR YET ANOTHER
FINE EARLY AUTUMN NIGHT ACROSS THE FORECAST AREA. OVERNIGHT TEMPS
SHOULD FALL TO THE 50-55 DEGREE RANGE IN MOST AREAS THANKS TO A
LITTLE MORE GRADIENT WIND AND ANOTHER COUPLE DEGREES OF MODERATION
IN TEMPS IN MANY AREAS TODAY OVER YESTERDAY. FRIDAY TO BE ANOTHER IN
A STRING OF NICE DAYS...WITH HIGHS 80-85...A BIT MORE BREEZY WITH
STRONGER SOUTH WINDS CONFINING ANY LAKE MICHIGAN COOLING TO THE
IMMEDIATE NORTH SHORE...AND A LITTLE MORE PATCHY THIN CIRRUS DURING
THE DAY.
CURRENT FORECAST HANDLES ALL OF THIS WELL...AND OTHER THAN A FEW
TWEAKS TO HOURLY GRIDS THIS EVENING...NO UPDATES NEEDED AT THIS
TIME.
RATZER
//PREV DISCUSSION...
354 PM CDT
NO REAL FORECAST CONCERNS THIS FORECAST PERIOD WITH A CONTINUED
WARMING TREND INTO THE WEEKEND.
UPPER LEVEL RIDGE REMAINS STRETCHED ACROSS THE REGION...BUT WITH
UPPER LEVEL RIDGE AXIS CONTINUING TO SLOWLY SHIFT EAST WITH TIME.
AT THE SURFACE A MORE RELAXED PATTERN REMAINS SITUATED OVER THE
CWA AS RIDGE OF HIGH PRESSURE SITS JUST TO THE EAST. THIS
CONTINUES TO HELP KEEP THIS PLEASANT WEATHER IN PLACE AS SUNNY
SKIES AND LIGHT FLOW PREVAILED ONCE AGAIN. TEMPS TODAY HAVE RISEN
ONCE AGAIN INTO THE 80S FOR MOST OF THE CWA WITH SOME AREAS ACROSS
THE FAR SOUTHERN PORTION OF THE CWA OBSERVING CLOSE TO THE MID 80
MARK. GUIDANCE CONTINUES TO UNDER DO TEMPS TODAY...SO HAVE
CONTINUED THE TREND OF GOING ABOVE GUIDANCE INTO THE WEEKEND.
TEMPS WILL CONTINUE TO WARM ON FRIDAY WITH 850S TEMPS CONTINUING
TO INCREASE WITH MAIN THERMAL AXIS OVERHEAD. HAVE FORECAST TEMPS
IN THE 80S FOR MOST OF THE CWA ON FRIDAY WITH FAR NORTHEAST
ILLINOIS THE EXCEPTION...STAYING IN THE UPPER 70S. A SOUTH WIND
WILL SHIFT MORE SOUTHEAST DURING THE DAY...HELPING TO KEEP COOLER
CONDITIONS IN THIS LOCATION. THEN TEMPS GOING INTO THE
WEEKEND...SATURDAY AND SUNDAY...HAVE STILL TRENDED SLIGHTLY ABOVE
GUIDANCE BUT WITH SOME SLIGHT UNCERTAINTY INTO FORECAST HIGHS OVER
THESE NEXT COUPLE OF DAYS AS UPPER LEVEL RIDGE BEGINS TO BREAK
DOWN/SHIFT EAST WITH 850 TEMPS COMING DOWN. ALTHOUGH A MORE
ORGANIZED PRESSURE GRADIENT AS WELL AS BETTER FLOW ALOFT WILL
PROVIDE BETTER SOUTHERLY FLOW. THIS SHOULD HELP ADVECT WARMER AIR
NORTH...INCLUDING ALL AREAS IN THE ENTIRE CWA. THIS INCLUDES ALL
AREAS ALONG THE LAKE...WITH TEMPS STILL MAKING IT INTO THE 80S.
NO REAL CHANCE FOR PRECIP UNTIL NEXT WEDNESDAY...BY LATE IN THE
DAY ON FRIDAY LARGE UPPER LEVEL LOW...CURRENTLY MOVING ACROSS THE
ROCKIES...WILL BEGIN TO LIFT NORTH WITH MODELS IN FAIR AGREEMENT
OF THIS UPPER LEVEL FEATURE PROGRESSING THROUGH THE NATIONS MID
SECTION. AS THIS OCCURS...FLOW BEGINS TO SHIFT WAVES/ENERGY TO THE
EAST BUT KEEPING THEM JUST TO THE NORTH...WHICH WILL CONTINUE TO
KEEP PRECIP AND CLOUD COVER ALSO TO THE NORTH. HENCE...PLEASANT
AND WARM WEATHER TO CONTINUE.
RODRIGUEZ
&&
.FIRE WEATHER...
332 AM CDT
CONTINUED DRY WEATHER THROUGH THE NEXT FEW DAYS WITH DEW POINTS
HOVERING IN THE MID/UPR 40S...POSSIBLY RISING TO 50 DEGREES
FRI AFTERNOON ACROSS PORTIONS OF NORTHERN ILLINOIS. WINDS AGAIN
TODAY WILL REMAIN LIGHT FROM THE SOUTH AROUND 10 MPH. AFTERNOON
TEMPERATURES ARE EXPECTED TO WARM TO THE LOWER 80S FOR MUCH OF THE
AREA...COUPLED WITH THE FORECAST DEW POINTS AND RELATIVE HUMIDITY
VALUES WILL FALL THIS AFTERNOON TO THE 20 TO 30 PERCENT RANGE
ACROSS MUCH OF THE AREA. 20 FT WINDS ARE EXPECTED TO BE SIMILAR TO
THE SFC CONDS.
FRIDAY WILL SEE SOME CHANGES WITH INCREASED WINDS...AROUND 15
MPH...AND BETTER MIXING. DEW POINTS MAY RISE INTO THE LOWER
50S...WHICH WILL AID IN KEEPING AFTERNOON RELATIVE HUMIDITY VALUES
BETWEEN 30 AND 40 PERCENT. HOWEVER CONFIDENCE IS LOW...AS
GENERALLY INCREASED WINDS AND LACK OF MOISTURE INDICATES DEW
POINTS WILL FALL IN THE AFTERNOON. THUS THE POTENTIAL FOR LOWER
RELATIVE HUMIDITY VALUES ACROSS ALL OF NORTHERN ILLINOIS.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* NO CONCERNS OVERNIGHT
* GUSTY SOUTH WINDS IN THE AFTERNOON
SHEA
//DISCUSSION...UPDATED 06Z...
SURFACE RIDGING TO THE EAST ACROSS THE OHIO VALLEY...COUPLED WITH
LOW PRESSURE ACROSS THE PLAINS...IS ALLOWING FOR LIGHT GRADIENT
FLOW FROM THE SOUTH. GRADIENT WILL TIGHTEN IN THE DAYTIME AND
ALLOW SOME OF THE HIGHER MOMENTUM AIR ALOFT TO MIX DOWN. THE
TIGHTER GRADIENT AND STRONGER WINDS EXPECTED TO REMAIN WEST AND
ACROSS THE MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS SUGGEST
PEAK GUSTS IN THE AFTERNOON IN THE MID TEENS FOR ORD/MDW...WHILE
RFD WILL LIKELY REACH THE LOWER 20 KT RANGE. ATMOSPHERE WILL AGAIN
DECOUPLE AFTER SUNSET ALLOWING WINDS TO AGAIN WEAKEN TO THE 6-9 KT
RANGE OUT OF THE SSE OVERNIGHT.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...CHANCE OF SHRA.
&&
.MARINE...
352 PM CDT
A LARGE HIGH STRETCHING FROM QUEBEC THROUGH NORTH CAROLINA WILL
BEGIN TO SETTLE SOUTH TO OVER THE MID ATLANTIC COAST THURSDAY
NIGHT. A DEEPENING LOW PRESSURE SYSTEM CURRENTLY OVER SOUTHERN
WYOMING WILL MOVE NORTHEASTWARD INTO MANITOBA BY SATURDAY MORNING AND
DEEPEN. THE LOW WILL THEN CONTINUE NORTHEASTWARD TO OVER HUDSON
BAY BY SATURDAY EVENING. THE MOVEMENT OF THE LOW WILL STRENGTHEN
THE PRESSURE GRADIENT OVER THE CENTRAL AND NORTHERN SECTIONS OF
LAKE MICHIGAN FRIDAY NIGHT...RESULTING IN WINDS OVER THE NORTHERN
HALF OF LAKE MICHIGAN INCREASING TO 20-25 KT. THE WARM LAKE
TEMPERATURES AND WARM AIRMASS OVERHEAD WILL CREATE STABLE
CONDITIONS...THEREFORE STRONGER WINDS WILL NOT BE ABLE TO MIX DOWN
TO THE LAKE SURFACE. WIND GUSTS WILL BE MINIMAL AT BEST FRIDAY AND
SATURDAY. WINDS WILL WEAKEN LATE ON SATURDAY AS THE LOW MOVES OVER
THE HUDSON BAY AND THE PRESSURE GRADIENT WEAKENS.
OTHERWISE...HIGH PRESSURE AND LIGHT FLOW WILL DOMINATE THE
PATTERN FOR THE EASTERN HALF OF THE UNITED STATES THROUGH THE
BEGINNING OF NEXT WEEK.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
