254 AM CDT
MAIN FORECAST CHALLENGE THIS MORNING IS WITH POTENTIAL FOR FROST
AGAIN TONIGHT.
THE POWER-HOUSE STORM THAT PUT ON ONE HECK OF A SHOW ALONG THE LAKE
MICHIGAN SHORE IS WEAKENING AND MOVING AWAY WITH HIGH PRESSURE
MOVING INTO THE REGION. PUSH OF CHILLY AIR IN THE WAKE OF THIS
STORM IS ALREADY BEING REPLACED WITH WARM AIR ADVECTION ALOFT TO
OUR WEST...WHICH SHOULD BEGIN TO SPREAD EAST INTO THE AREA TODAY.
WITH FULL/NEARLY FULL SUNSHINE AND DRY AIR MASS IN PLACE WOULD
ANTICIPATE A HEALTHY REBOUND IN TEMPS THIS AFTERNOON.
TEMPS AND SUBSEQUENT FROST POTENTIAL IS TRICKY FOR TONIGHT. MOSTLY
CLEAR SKIES AND REASONABLY GOOD CHANCE OF WINDS GOING NEARLY CALM
WOULD CERTAINLY FAVOR STRONG RADIATIONAL COOLING. HOWEVER...ALOFT
TEMPERATURES WILL BE WARMING RAPIDLY...WITH MODEL PROGGED 925MB
TEMPS NEARLY 10C WARMER THAN THIS MORNING...SO AM SOMEWHAT CONCERNED
ABOUT JUST HOW COLD/DECOUPLED WE WILL BECOME. WE STAND A REASONABLY
GOOD CHANCE OF AREAS OF FROST OVER OUR SE CWA...BUT WILL LET THE DAY
SHIFT RE-ACCESS AND PULL THE TRIGGER ON ANY POSSIBLE HEADLINES.
REALLY LOOKING LIKE A SPECTACULAR LATE OCT WEEKEND ALL THINGS
CONSIDERED WITH UPPER RIDGE BUILDING IN AND TEMPS RECOVERING BACK TO
ABOVE SEASONAL NORMS. WEAK SHORTWAVE AND ASSOCIATED FRONT APPROACH
FROM THE NORTHWEST LATER SUNDAY AND HAVE CONTINUED WITH LOW CHANCE
POPS WITH THIS FEATURE. MOISTURE LOOKS TO BE FAIRLY LIMITED...BUT
WITH STEEP LAPSE RATES HARD TO COMPLETELY RULE OUT SOME SCATTERED
CONVECTION ALONG THE FRONT.
MORE SIGNIFICANT SHORTWAVE PROGGED TO ARRIVE TUESDAY...BUT MEDIUM
RANGE MODELS CONTINUE TO BOUNCE AROUND WITH RESPECT TO THE TRACK
OF THE SURFACE LOW. SHOULD IT GO NORTH...WE COULD BE QUITE MILD
WITH SOUTHERLY WINDS...CONVERSELY IF IT GOES FARTHER SOUTH LIKE
THE GFS/DGEX SUGGEST THEN STIFF EAST WINDS SHOULD KEEP IT CHILLY.
UNTIL THE MODELS SETTLE ON A SOLUTION PROBABLY BEST TO MAKE NO
MAJOR CHANGES TO GOING FORECAST FOR NOW.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 08Z...
* NO CONCERNS.
BMD
//DISCUSSION...UPDATED 06Z...
NO SIGNIFICANT CONCERNS FOR THE LATEST FORECAST. LINGERING VFR CLOUD
COVER FROM DEPARTING LOW WILL GRADUALLY ERODE FROM THE WEST AS
ANTICYCLONIC FLOW PUSHES EAST ACROSS THE FORECAST AREA. GUSTY WINDS
HAVE ENDED ACROSS THE AREA AND WINDS WILL GRADUALLY BACK TO THE WEST
THEN SOUTHWEST THROUGH THE FORECAST PERIOD AND REMAIN LIGHT...LESS
THAN 10 KT...AS THE RIDGE AXIS MOVES THROUGH THE AREA. BMD
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN ALL ELEMENTS OF FORECAST.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
* SATURDAY...VFR
* SUNDAY...CHANCE SHRA
* MONDAY...VFR
* TUESDAY AND WEDNESDAY...CHANCE SHRA
SHEA
&&
.MARINE...
155 PM CDT
WINDS WILL CONTINUE TO GRADUALLY DIMINISH ACROSS LAKE MICHIGAN
THROUGH TONIGHT...AS DEEP LOW PRESSURE LIFTS TO THE NORTHEAST ALONG
THE EAST SHORE OF LAKE HURON AND INTO EASTERN ONTARIO.
EARLY AFTERNOON OBSERVATIONS AROUND THE LAKE INDICATE WINDS HAVE
EASED INTO THE 35-40 KT RANGE FOR THE MOST PART...THOUGH STILL A FEW
GUSTS INTO THE MID 40S AROUND SOUTH HAVEN MICHIGAN. BASED ON THIS...
AND THE EXPECTED TREND OF GRADUALLY DIMINISHING WINDS...WILL GO
AHEAD AND LET THE STORM WARNING END FOR THE OPEN WATERS AND INDIANA
NEAR SHORE ZONES...REPLACING THESE HEADLINES WITH A GALE WARNING
WHICH WILL CONTINUE THROUGH 06Z/1 AM CDT. WINDS MAY FALL BELOW GALE
A BIT EARLIER...BUT PREFER TO HAVE TO CANCEL EARLY RATHER THAN
EXTEND GALE HEADLINES LATER THIS EVENING. WINDS WILL CONTINUE TO
SLACKEN ON FRIDAY...AS THE LOW PULLS AWAY AND FILLS AND WEAK HIGH
PRESSURE RIDGING MOVES INTO THE WESTERN LAKES.
FOR THE ILLINOIS NEARSHORE AREAS...WILL MAINTAIN GALE WARNING
THROUGH 00Z/7 PM CDT WHICH WILL THEN ALLOW DOWNGRADE TO A SMALL
CRAFT ADVISORY AT THAT TIME.
LATER IN THE FORECAST PERIOD...A COUPLE OF TRANSIENT LOW PRESSURE
SYSTEMS WILL AFFECT THE REGION. ONE WEAKER LOW IS EXPECTED TO PASS
ACROSS THE NORTHERN LAKES ON SUNDAY...AND IS PROGGED TO DEEPEN
SLIGHTLY AS IT MOVES OFF TO THE EAST MONDAY. THIS WILL LIKELY
PRODUCE A RELATIVELY SHORT PERIOD OF GUSTY WEST WINDS AROUND 25 KTS.
A SECOND LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP LATE TUESDAY AND
WEDNESDAY ACROSS REGION. MODEL FORECASTS EXHIBIT QUITE A BIT OF
SPREAD IN LOCATION/STRENGTH AT THIS TIME...SO HAVE STAYED WITH
BLENDED GUIDANCE SOLUTION WHICH MAY ULTIMATELY END UP BEING TOO LOW
WITH WIND SPEEDS. THIS WILL BE MONITORED FOR MORE DETAIL AS FURTHER
MODEL RUNS GET A BETTER HANDLE ON THIS SYSTEM FOR THE MIDDLE OF NEXT
WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ019-ILZ020-ILZ021-ILZ032 UNTIL 9 AM FRIDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 PM
FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM FRIDAY.
&&
$$
