342 AM CDT
MAIN CONCERNS/ISSUES ARE WITH THE NEXT CHANCES FOR PRECIP ON
SUNDAY AND SUNDAY NIGHT...WITH A SLIGHT WARMING TREND INTO THE
START OF NEXT WEEK.
LATEST SATELLITE IMAGERY SHOWING LONGWAVE TROUGH AND ASSOCIATED
TROUGH OF LOW PRESSURE SLOWLY PUSHING THROUGH THE CENTRAL GREAT
LAKES REGION EARLY THIS MORNING. OUT AHEAD OF THESE
FEATURES...PRECIP CONTINUES TO SHIFT EAST OVER THE LAKE AND ACROSS
PORTIONS OF NORTHWEST INDIANA. LATEST RUC ANALYSIS STILL
INDICATING VERY STEEP MID LEVEL LAPSE RATES OVERHEAD THIS
MORNING...WITH VERY STEEP LOW LEVEL LAPSE RATES SITUATED OVER THE
LAKE. THIS HAS RESULTED WITH SOME ISOLATED THUNDER EMBEDDED WITHIN
THESE SHOWERS ACROSS THE SOUTHERN HALF OF THE LAKE. WITH THE
SYSTEMS EASTERLY PROGRESSION...EXPECT ANY LINGERING MOISTURE TO
CONTINUE TO EXIT OVER THE NEXT SEVERAL HOURS. ON THE BACKSIDE OF
THIS SYSTEM...CLEARING HAS BEEN OBSERVED WITHIN THE LAST COUPLE OF
HOURS WITH ALL OF NORTHERN ILLINOIS CURRENTLY CLEAR. THESE
CLEARING SKIES AND LIGHT SOUTH/SOUTHWEST WINDS HAS RESULTED IN
SOME GOOD TEMPERATURES DROPS WITH MANY AREAS IN THE NORTHWEST CWA
FALLING TO THE LOW TO MID 30S. EXPECT TEMPS IN THIS LOCATION TO
CONTINUE TO FALL OVER THE NEXT COUPLE OF HOURS WITH THE REMAINING
CWA TO FOLLOW. AS TEMPS FALL INTO THE LOWER 30S...CURRENT FREEZE
WARNING WILL CONTINUE TO BE VALID THIS MORNING. WITH THE UPPER
LEVEL TROUGH SHIFTING EAST...HIGH PRESSURE AND DRIER AIR WILL
BUILD ACROSS THE REGION PROVIDING MOSTLY SUNNY SKIES TODAY. WITH
THIS SUNSHINE IN PLACE...MOST LOCATIONS SHOULD OBSERVE HIGH
TEMPERATURES IN THE MID 50S WITH EVEN SOME UPPER 50S FORECAST
ACROSS THE SOUTHERN HALF OF THE CWA.
ALTHOUGH AS QUICKLY AS THIS LAST SYSTEM EXITS...THE NEXT SYSTEM
WILL APPROACH FROM THE NORTHWEST LATE TONIGHT INTO EARLY SUNDAY
MORNING. WITH A BRIEF PERIOD OF RIDGING ACROSS PORTIONS OF THE
MIDWEST TODAY AND TONIGHT...HEIGHTS WILL FALL ON SUNDAY AS AN
UPPER LEVEL TROUGH DIGS SOUTH FROM THE NORTHERN PLAINS. THIS UPPER
LEVEL TROUGH AND SHORT WAVE TROUGH WILL ALLOW A SURFACE TROUGH OF
LOW PRESSURE TO DEVELOP AND MOVE EAST THROUGH THE UPPER
MISSISSIPPI VALLEY. ALTHOUGH...FORECAST MODELS CONTINUE TO SHOW
SOME SLIGHT DIFFERENCES IN THE EXACT EVOLUTION/TRACK OF THIS
TROUGH AND ASSOCIATED SURFACE FEATURE. NONETHELESS...IT WOULD
APPEAR AT THIS TIME THAT THE BEST CHANCES FOR SHOWERS WILL BE
ACROSS THE NORTHERN PORTION OF THE CWA COME SUNDAY AFTERNOON. SO
DESPITE THE DIFFERENCES AMONGST THE MODELS...THE LIKELIHOOD OF
OBSERVING PRECIP WITHIN THIS AREA IS INCREASING AND HAVE ADJUSTED
POPS DURING THIS TIME TO REFLECT THIS. ALTHOUGH A WARMER AIR MASS
WILL ADVECT OUT AHEAD OF THIS SYSTEM ON SUNDAY...DONT THINK TEMPS
WILL REFLECT THIS AS A GOOD AMOUNT OF CLOUD COVER/PRECIP WILL BE
OVERHEAD HELPING TO LIMIT ANY WARMING.
FORECAST MODELS CONTINUE TO INDICATE THAT THIS UPPER LEVEL TROUGH
WILL REMAIN FAIRLY PROGRESSIVE IN NATURE...WITH IT AND THE
SURFACE TROUGH EXITING BY MONDAY MORNING. SKIES WILL BE CLEARING
WITH UPPER LEVEL RIDGING ONGOING ACROSS THE REGION ON MONDAY. THIS
WILL RESULT IN SOUTHERLY FLOW SETTING UP AND WAA TO OCCUR OVER THE
CENTER CONUS WITH 850 TEMPS ON THE RISE. A DRY AND WARMING PERIOD
IS FORECAST MONDAY INTO TUESDAY WITH HIGH TEMPS OF AROUND 60 AND
EVEN THE LOWER 60S POSSIBLE BY TUESDAY. ALTHOUGH THE NEXT UPPER
LEVEL SYSTEM WILL BE APPROACHING ONCE AGAIN COME WEDNESDAY WITH
PRECIP CHANCES ON THE INCREASE AND COOLER TEMPS FORECAST BY THE
MIDDLE PART OF THE WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ENDING OF SHOWERS AND WIND SHIFT FROM SOUTH TO WEST-NORTHWEST
DURING PRE-DAWN HOURS.
RATZER
//DISCUSSION...UPDATED 06Z...
WEAK SURFACE TROUGH/COOL FRONT WAS MOVING SLOWLY ACROSS NORTHERN
ILLINOIS EARLY THIS MORNING...AND SHOULD MOVE THROUGH KRFD SHORTLY
AND ACROSS CHICAGO AREA TERMINALS 09-10Z. TRAILING EDGE OF
SCATTERED SHOWERS AHEAD OF THIS FRONT WERE ALREADY MOVING THROUGH
KORD/KMDW AND SHOULD BE PAST KGYY AFTER 07Z OR SO. SOUTH-SOUTHWEST
WINDS LESS THAN 10 KTS AHEAD OF THE FRONT WILL SHIFT TO THE WEST
WITH FROPA. GOES IR SATELLITE IMAGERY DEPICTS FAIRLY QUICK
TRANSITION TO CLEAR SKIES BEHIND THE FRONT. WHILE SOME PATCHY
GROUND FOG NOT COMPLETELY OUT OF THE QUESTION AS SKIES CLEAR OVER
MOIST GROUND IN LIGHT GRADIENT...AIR IS FAIRLY DRY JUST ABOVE THE
SURFACE AND DRIER AIR WILL FILTER IN BEHIND THE FRONT OVERNIGHT.
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE REMAINDER OF
THE TAF PERIOD.
SURFACE HIGH PRESSURE RIDGE SPREADS ACROSS TERMINALS LATE
SATURDAY AFTERNOON AND EVENING...WITH WEST-NORTHWEST WINDS AROUND
10 KT DURING THE DAY DECREASING AND BACKING TO THE SOUTH AGAIN IN
THE EVENING. MID/HIGH CLOUDS WILL INCREASE LATE SATURDAY NIGHT AS
NEXT SYSTEM APPROACHES.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE ALL ELEMENTS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE OF SHOWERS WITH MVFR CIGS POSSIBLE.
MONDAY...MVFR POSSIBLE EARLY...THEN VFR.
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA WITH MVFR POSSIBLE.
THURSDAY...MVFR POSSIBLE EARLY.
MDB
&&
.MARINE...
323 AM CDT
THE MAIN MARINE FORECAST CONCERN THIS MORNING IS WITH SOUTH GALES
DEVELOPING ON THE SOUTH HALF OF LAKE MICHIGAN SUNDAY MORNING AS
LOW PRESSURE DROPS SOUTHEAST ACROSS THE UPPER MIDWEST. MODELS ARE
IN GOOD AGREEMENT IN SOUTH WINDS STRENGTHENING RAPIDLY AS THE
GRADIENT TIGHTENS AHEAD OF THE LOW...WITH FORECAST SOUNDINGS
DEPICTING WINDS INCREASING ABOVE 30 KTS WITHIN THE MIXED LAYER BY
MID MORNING. THE LOW WILL THEN BEGIN TO FILL BY EVENING AS IT
DRIFTS EAST...WITH GALES DROPPING OFF FAIRLY QUICKLY LATE IN THE
DAY. BASED ON THIS HAVE HOISTED A GALE WARNING FOR THE OPEN WATERS
OF SOUTHERN LAKE MICHIGAN FOR SUNDAY.
FOR THE ILLINOIS AND INDIANA NEARSHORE WATERS...WINDS WILL LIKELY
GUST TO 30 KTS FOR A TIME SUNDAY. WILL HAVE A SMALL CRAFT ADVISORY
FROM EARLY SUNDAY MORNING THROUGH EARLY SUNDAY EVENING.
THE LOW WILL CONTINUE TO FILL AS IT DRIFTS EAST ACROSS THE LAKE
LATER SUNDAY NIGHT AND MONDAY. DEEPER LOW PRESSURE WILL MOVE
ACROSS CENTRAL CANADA EARLY NEXT WEEK...SETTING UP A PERIOD OF
SOUTHWEST FLOW ACROSS THE WESTERN LAKES REGION.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZE WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 9 AM SATURDAY.
IN...FREEZE WARNING...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 9 AM
SATURDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM
SUNDAY TO 7 PM SUNDAY.
&&
$$
