347 AM CDT
MAIN CONCERNS/ISSUES ARE WITH PRECIP TRENDS TODAY INTO
TONIGHT...ALONG WITH A WARMING TREND ANTICIPATED THROUGH THE
MIDDLE PART OF THE WEEK.
LATEST SATELLITE IMAGERY DEPICTING CURRENT LONGWAVE TROUGH ACROSS
THE CENTRAL PLAINS DIGGING SOUTH ALONG WITH ATTENDANT SURFACE
TROUGH AND ASSOCIATED FRONTAL BOUNDARIES LOCATED NEAR
MINNESOTA/IOWA THIS MORNING. AS THESE FEATURES SHIFT EAST EARLY
THIS MORNING...SHOWERS CAN BE SEEN SPREADING EAST ACROSS PORTIONS
OF IOWA...AND EXPECT THESE SHOWERS AND CLOUD COVER TO MOVE EAST
ACROSS THE REGION WITH TIME TODAY. LATEST GUIDANCE IN FAIR
AGREEMENT WITH TAKING THIS UPPER LEVEL TROUGH AND SURFACE
REFLECTION EAST ACROSS SOUTHERN WISCONSIN BY LATER THIS AFTERNOON
INTO EARLY EVENING. AS THIS OCCURS...LARGE SCALE FORCING WILL
INCREASE MORE FROM WEST TO EAST ACROSS THE CWA WITH THE BEST
FORCING TO COME LATER THIS AFTERNOON. ALTHOUGH...LATEST SURFACE
OBSERVATIONS CONTINUE TO INDICATE A VERY DRY AIRMASS IN PLACE WITH
DEWPOINTS CURRENTLY IN THE MID 20S. LAST NIGHTS 00Z OBSERVED
SOUNDINGS FROM ACROSS THE AREA WERE ALSO SHOWING THIS DRY AIR MASS
WITH VERY DRY LOWER LEVELS. ALTHOUGH MOISTURE WILL BE ON THE
INCREASE INTO THIS AFTERNOON...DONT THINK THIS PRECIP SHIELD WILL
REALLY SHIFT OVERHEAD UNTIL THE MID TO LATE AFTERNOON. AS THIS
OCCURS...THE COLUMN WILL SATURATE AND MOST OF THE CWA SHOULD
OBSERVE SHOWERS. DID LOWER POPS JUST A LITTLE BRINGING THEM DOWN
TO LIKELY FOR THIS AFTERNOON...BUT DID NOT MAKE THIS CHANGE DUE TO
OVERALL CONFIDENCE. DID THIS MORE DUE TO THE FACT OF THIS DRIER
AIR IN PLACE AND THE POSSIBLE LIGHTER NATURE OF THESE SHOWERS IN
SOME PLACES. THE BEST CHANCES FOR PRECIP CONTINUE TO BE ACROSS THE
NORTHERN HALF OF THE CWA TIED CLOSER TO UPPER LEVEL TROUGH/SURFACE
LOW...WITH THESE AREAS ALSO OBSERVING MORE AMOUNTS. INSTABILITY
DURING THIS TIME FRAME WILL REMAIN NON EXISTENT ACROSS THE REGION
WITH PRECIP REMAINING SHOWERS. ALTHOUGH...LATEST HIGH RES DATA IS
HINTING AT THE POSSIBILITY OF SOME CONVECTIVE ELEMENTS FORMING ON
THE BACKSIDE OF THE MAIN PRECIP SHIELD...MORE TOWARDS THIS
EVENING. BASED ON LATEST DATA...THIS WOULD SEEM TO BE A SLIGHT
POSSIBILITY. MODELS INDICATING THAT DRIER AIR/STEEPER MID LEVEL
LAPSE RATES WILL POSSIBLY MOVE OVERHEAD DURING THIS TIME...THUS
CREATING CONVECTIVELY UNSTABLE CONDITIONS. AM NOT QUIET CONFIDENT
AS TO THESE EXACT DETAILS AT THIS TIME...SO HAVE OPTED TO LEAVE
OUT ANY MENTION OF THUNDER. A MORE LIKELY SCENARIO WOULD BE AN
INCREASE IN RAINFALL RATES AS OPPOSED TO ANY POSSIBLE THUNDER.
CLOSED UPPER LEVEL TROUGH LATE TONIGHT AND EARLY MONDAY SHOULD
BECOME MORE OPEN AND SLOWLY SHIFT EAST WITH TIME. SHOWERS WILL BE
ENDING DURING THIS TIME...BUT WITH CLOUD COVER TO POSSIBLY LINGER
INTO MONDAY AFTERNOON. THEN WITH THE DEPARTURE OF THIS UPPER LEVEL
TROUGH...RIDGING WILL BE ONGOING WITH A WARMER AIR MASS SHIFTING
OVER AND A DRY PERIOD EXPECTED INTO EARLY WEDNESDAY. WITH A STEADY
STREAM OF SOUTHERLY FLOW AND THERMAL AXIS SHIFTING ACROSS THE
REGION...HAVE RAISED POPS TUESDAY AND WEDNESDAY WITH HIGHS LOOKING
MORE LIKELY TO BE IN THE LOW TO MID 60S. WITH MODELS TRENDING MORE
TOWARDS A SLOWER PROGRESSION OF THE NEXT SYSTEM...WEDNESDAY TEMPS
AND CONDITIONS APPEAR TO BE ON THE UP. ALTHOUGH...FOR SURE
PRECIP/CLOUD COVER WILL BE ON THE INCREASE WEDNESDAY NIGHT INTO
THURSDAY AS THIS SYSTEM SHIFTS EAST.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LIGHT AND VARIABLE WINDS TURNING SOUTH/SOUTHEAST OVERNIGHT THEN
BECOMING GUSTY TO AROUND 25 KT MID/LATE MORNING.
* SHOWER CHANCES INCREASING THIS AFTERNOON.
* LOWERING VFR CIGS THIS AFTERNOON.
RATZER
//DISCUSSION...UPDATED 06Z...
VERY LITTLE CHANGE TO PREVIOUS FORECAST THINKING...WITH NEW 00Z
GUIDANCE VERY SIMILAR TO EARLIER RUNS.
WEAK HIGH PRESSURE WILL MOVE OFF TO THE EAST OF THE TERMINALS
EARLY THIS MORNING AS LOW PRESSURE DEVELOPS INTO THE UPPER
MISSISSIPPI VALLEY. LIGHT VARIABLE WINDS WILL BECOME SOUTHEAST IN
RESPONSE TO THE SURFACE PRESSURE FALLS...AND WILL GRADUALLY
INCREASE AND BECOME GUSTY DURING THE MORNING AS THE PRESSURE
GRADIENT TIGHTENS AHEAD OF THE LOW. GUSTS TO 25 KNOTS ARE LIKELY
BY MID-DAY. THE GRADIENT WILL THEN WEAKEN BY LATE AFTERNOON...AS
THE LOW MOVES INTO WISCONSIN AND BEGINS TO FILL. THIS WILL ALLOW
WINDS TO DIMINISH AND SHIFT SOUTHWEST.
MID AND HIGH CLOUD VFR CEILINGS WILL DEVELOP EARLY THIS MORNING
AND WILL ONLY GRADUALLY LOWER THIS MORNING. DRY AIR IN THE LOW
LEVELS WILL TAKE SOME TIME TO SATURATE...WITH RAIN CHANCES
INCREASING DURING THE AFTERNOON HOURS. CIGS WILL LIKELY LOWER INTO
LOW END VFR DURING SHOWERS THIS AFTERNOON...AND THOUGH SOME PATCHY
MVFR CIGS ARE POSSIBLE VFR CONDITIONS SHOULD GENERALLY PREVAIL.
LOWER CLOUDS SHOULD SCATTER OUT DURING THE EVENING AS THE LOW
LEVEL FLOW BECOMES SOUTHWEST BEHIND THE COLD FRONT TRAILING THE
LOW.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN LIGHT AND VARIABLE WINDS TURNING SOUTHERLY BY
SUNRISE AND GUSTS INCREASING TO AROUND 25 KT MID/LATE MORNING.
* MEDIUM-HIGH CONFIDENCE IN SHRA AFFECTING THE TERMINALS SUNDAY
AFTERNOON/EARLY EVENING.
* MEDIUM CONFIDENCE THAT CEILINGS WILL LOWER TO LOW END VFR SUNDAY
AFTERNOON.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...MVFR CIGS POSSIBLE IN THE MORNING...OTHERWISE VFR.
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MAINLY VFR.
THURSDAY...CHANCE SHRA...MVFR CIGS POSSIBLE.
FRIDAY...VFR.
MDB
&&
.MARINE...
256 AM CDT
SOUTH-SOUTHEAST GALES ARE EXPECTED ON THE CENTRAL AND SOUTHERN
PORTIONS OF LAKE MICHIGAN TODAY.
LOW PRESSURE DEVELOPING ALONG THE IOWA-MINNESOTA BORDER EARLY THIS
MORNING WILL RESULT IN A TIGHTENING OF THE SURFACE PRESSURE
GRADIENT ACROSS LAKE MICHIGAN THIS MORNING...WITH WINDS QUICKLY
INCREASING TO GALE FORCE BY MID-MORNING. GALES IN THE 35-40 KT
RANGE WILL LIKELY LAST THROUGH THE AFTERNOON INTO THE EARLY
EVENING HOURS...BEFORE THE LOW MOVES INTO WISCONSIN AND BEGINS TO
FILL ALLOWING THE PRESSURE GRADIENT TO WEAKEN AND WINDS TO EASE
AND VEER TO THE SOUTHWEST. THE LOW WILL THEN CONTINUE TO WEAKEN TO
AN OPEN TROUGH AS IT LIFTS NORTH-NORTHEAST ACROSS THE NORTHERN
LAKES MONDAY.
STRONGER LOW PRESSURE FAR TO THE NORTH OVER CANADA WILL TRAIL A
COLD FRONTAL TROUGH THROUGH THE UPPER MIDWEST MONDAY NIGHT INTO
TUESDAY PRODUCING A PERIOD OF SOUTHWEST WINDS TROUGH MID-WEEK
BEFORE THE FRONT SLIPS SOUTHEAST ACROSS THE WESTERN LAKES.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ004-ILZ005-ILZ011-ILZ012-ILZ013-ILZ020-
ILZ021-ILZ022-ILZ023-ILZ033 UNTIL 8 AM SUNDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 8 AM
SUNDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM
SUNDAY TO 9 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...7 AM SUNDAY TO 10 PM SUNDAY.
&&
$$
