315 AM CDT
PRIMARY FORECAST CHALLENGES THIS MORNING INCLUDE TEMPS TUES AND THE
SUBSEQUENT PRECIP CHANCES WITH WAVY FROPA.
UPPER TROUGH AND ASSOCIATED WEAK COLD FRONT CURRENTLY SWEEPING
ACROSS THE CWA SHOULD CLEAR THE AREA BY SUNRISE. THIS SHOULD SET
THE STAGE FOR ANOTHER SPECTACULAR AUTUMN DAY WITH SUNNY SKIES AND
SLIGHTLY ABOVE AVERAGE TEMPERATURES...THOUGH LIKELY SEVERAL
DEGREES COOLER THAN SUNDAY.
SHORTWAVE TROUGH CURRENTLY MAKING LANDFALL OVER THE PACIFIC
NORTHWEST IS PROGGED TO CONTINUE EASTWARD WITH LEE SIDE LOW FORECAST
TO DEVELOP TONIGHT WITH WARM FRONTOGENESIS TAKING PLACE EAST OF THIS
LOW INTO SOUTHERN WISCONSIN. SOUTHERLY WINDS WILL BEGIN TO RAMP UP
EVEN LATE TONIGHT WHICH WILL LIKELY RESULT IN TEMPS LEVELING OFF
EARLY AND EVEN BEGIN TO RISE SLOWLY LATE TONIGHT...ESPECIALLY
WESTERN CWA. WITH CWA PROGGED TO BE SOLIDLY LOCATED SOUTH OF THE
WARM FRONT WOULD ANTICIPATE ASSOCIATED SHOWER/THUNDERSTORM ACTIVITY
TONIGHT TO DEVELOP NORTH OF THE WISCONSIN BORDER.
TEMPERATURES TUESDAY ARE GOING TO BE QUITE TRICKY. LOW LEVEL
MOISTURE SHOULD BE RATHER SLOW TO RETURN...SO STRATUS/CUMULUS
SHOULDNT BE MUCH OF A FACTOR UNTIL VERY LATE IN THE DAY. GFS/WRF-NAM
BOTH SUGGEST THAT THE BRUNT OF THE CIRRUS SHOULD REMAIN NORTH OF OUR
CWA IN CLOSER PROXIMITY TO THE 120KT UPPER LEVEL JET. BIGGEST WILD
CARD IS POTENTIAL FOR MID LEVEL CLOUDINESS...WHICH GIVEN THE PROGGED
DRAMATIC STEEPENING OF MID LEVEL LAPSE RATES...IT WOULDNT BE HARD TO
ENVISION FAIRLY EXTENSIVE ALTOCUMULUS DECK WITH EVEN SOME POTENTIAL
FOR VIRGA/LIGHT SHOWERS. GIVEN THIS...HAVE REMAINED MODESTLY
CONSERVATIVE WITH HIGH TEMPS...HOWEVER IF MID LEVEL CLOUD DECK
DOESNT MATERIALIZE EARLY ENOUGH OR EXTENSIVELY ENOUGH THEN RECORD
HIGHS COULD BE IN JEOPARDY.
MODELS HAVE COME AROUND TO A SOLUTION MUCH LIKE WHAT PREVIOUS
WRF-NAM RUNS HAD BEEN SHOWING WITH A MUCH LESS AMPLIFIED UPPER
TROUGH AND WEAKER/FARTHER SOUTH SURFACE LOW TRACK. MINIMAL HEIGHT
FALLS...WEAKER LARGE SCALE ASCENT...AND SOMEWHAT MEAGER MOISTURE
RETURN ALL DONT BODE PARTICULARLY WELL REGARDING THE PROSPECTS FOR
BREAKING THE CAP ASSOCIATED WITH THE IMPRESSIVE EML THAT IS
PROGGED TO ADVECT EASTWARD INTO THE AREA. WILL MAINTAIN CHANCE
POPS FOR SHOWERS/THUNDERSTORMS...BUT HAVE BACKED OFF SOMEWHAT ON
THE VALUES GIVEN THE TENDENCY TOWARD A LESS AMPLIFIED SOLUTION.
SURFACE FRONT SHOULD SWEEP ACROSS THE CWA TUESDAY EVENING BEFORE
STALLING OUT TO OUR SOUTH AS ANOTHER WIGGLE IN THE UPPER FLOW
MIGRATES NORTHEASTWARD. MODELS DIFFER WITH RESPECT TO THE AMPLITUDE
OF THIS WAVE AND SUBSEQUENTLY WHAT/IF ANY IMPACTS IT WILL HAVE ON
OUR CWA. GIVEN THE WRF-NAM'S RECENT PERFORMANCE HANDLING THIS SYSTEM
AND SINCE MANY MODELS HAVE BEGUN TO TREND THIS WAY...HAVE OPTED TO
HIT RAIN CHANCES HARDER FOR WEDNESDAY. IF WRF-NAM WERE TO VERIFY
WEDNESDAY WOULD BE A PRETTY DISMAL DAY WITH RAIN...LOW CLOUDS...AND
A STIFF NORTH WIND KEEPING TEMPS NEARLY STEADY OR EVEN FALLING
SLOWLY INTO 40S.
RE-ENFORCING SHOT OF COLD AIR IS SCHEDULED TO ARRIVE FRIDAY AS
ANOTHER SHORTWAVE HELPS RE-ESTABLISH THE TROUGH OF THE NE CONUS AND
EASTERN CANADA. HAVE MAINTAINED SOME SMALL PRECIP CHANCES WITH THIS
FROPA BUT GENERALLY EXPECTING DRY AND SEASONABLY COOL WX TO PERSIST
LATE THIS WEEK INTO THE WEEKEND.
IZZI
&&
.FIRE WEATHER...
315 AM CDT
TUESDAY AFTERNOON WILL NEED TO BE MONITORED FOR POTENTIAL INCREASED
FIRE DANGER AS UNSEASONABLY WARM CONDITIONS AND STRONG WINDS ARE
EXPECTED. ONE OF THE BIGGER WILD CARDS IS WITH RESPECT TO HOW MUCH
CLOUDINESS THERE WILL BE...SHOULD CLOUDS END UP BEING LESS PROMINENT
THEN SUNSHINE WOULD LIKELY RESULT IN BETTER MIXING. THIS WOULD
LIKELY RESULT IN WARMER TEMPERATURES...LOWER DEWPOINTS/RH...AND
STRONGER WIND GUSTS. AT THIS POINT THE POTENTIAL FOR RED FLAG
CRITERIA BEING MET APPEARS LOW...BUT IT WOULDNT BE TOO GREAT OF A
STRETCH FOR THERE TO BE WIND GUSTS OVER 30 MPH AND RH VALUES
DROPPING TO 30-35 PERCENT. THE GREATEST POTENTIAL FOR CONDITIONS TO
BECOME MORE PROBLEMATIC FOR FIRE WEATHER WILL BE OVER NORTHWEST
INDIANA AND SOUTH OF INTERSTATE 80 IN ILLINOIS. FARTHER NORTH AND
WEST CLOUD COVER AND SLIGHTLY HIGHER RH SHOULD LESSEN THE FIRE
WEATHER DANGER SOMEWHAT.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHWEST WINDS BECOMING WEST THROUGH THE DAY...WITH AN
OCCNL MID TEEN GUST
* GUSTY SOUTHERLY WINDS TUESDAY
* CHANCES FOR SHRA/TSRA TUESDAY AFTERNOON
SHEA
//DISCUSSION...UPDATED 12Z...
NORTHWEST WINDS WILL BE WITH US TO BEGIN THE PERIOD...SHIFTING TO
WESTERLY DURING THE DAY TODAY. WIND SPEEDS WILL PICK UP TO 10-12
KT BY 19Z AS THE RIDGE OF HIGH PRESSURE PASSES THROUGH THE AREA
AND MIXING GETS GOING. BEHIND THE RIDGE AXIS...WINDS TURN
SOUTHERLY THIS EVENING. LOOKING AHEAD TO TOMORROW...A WARM FRONT
WILL PASS THROUGH THE AREA TOMORROW EVENING. PRIOR TO THE
FROPA...WESTERLY WINDS WILL PICK UP IN THE AFTERNOON WITH GUSTS UP
TO 25 KT. A COLD FRONT PASSES THROUGH THE REGION LATE TUESDAY
AFTERNOON...WITH A CHANCE OF SHRA AND TSRA LATE IN THE AFTERNOON
THROUGH EARLY TUESDAY NIGHT.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS THROUGH THE DAY
SHEA
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...STRONG/GUSTY WESTERLY WINDS SHIFTING NORTH. MVFR
CIGS POSSIBLE LATE. CHANCE OF SHRA. CHANCE OF TSRA.
WEDNESDAY...MVFR/IFR POSSIBLE EARLY. CHANCE OF SHRA.
THURSDAY AND FRIDAY...SLIGHT CHANCE OF SHRA.
SATURDAY AND SUNDAY...VFR.
JEE
&&
.MARINE...
217 AM CDT
LOW PRESSURE MOVING ACROSS SOUTHERN ONTARIO THIS MORNING HAS PUSHED
A COLD FRONT ACROSS LAKE MICHIGAN. WESTERLY WINDS IN THE WAKE OF
THIS FRONT WILL CONTINUE TODAY...BUT THEY ARE EXPECTED TO SLOWLY ABATE
THROUGHOUT THE AFTERNOON.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO MOVE INTO NORTHERN
ILLINOIS LATER ON TUESDAY. AS THIS OCCURS...A WARM FRONT EXTENDING
TO THE EAST OF THIS LOW MAY LIFT ACROSS PORTIONS OF SOUTHERN LAKE
MICHIGAN. THIS WARM FRONT WILL LIKELY BE A MAJOR TRANSITION ZONE
BETWEEN GUSTY SOUTHERLY WINDS SOUTH OF THE FRONT...TO GUSTY
NORTHEASTERLY WINDS TO THE NORTH. GUSTY OFFSHORE SOUTHERLY WINDS
MAY BE STRONG ENOUGH TO RESULT IN SMALL CRAFT CONDITIONS FOR THE
INDIANA AND POSSIBLY THE ILLINOIS NEAR SHORE WATERS...DEPENDING ON
THE NORTHWARD EXTENT OF THE WARM FRONT. THERE CONTINUES TO BE
UNCERTAINTY ON THE EXACT NORTHWARD EXTENT OF THE WARM FRONT. BECAUSE
OF THIS...WE WILL HOLD OFF ON ANY HEADLINES AT THIS TIME.
THE LOW/COLD FRONT WILL PUSH SOUTH OF THE LAKE BY WEDNESDAY. THIS
WILL ALLOW GUSTY NORTHERLY WINDS TO DEVELOP ACROSS THE ENTIRE LAKE.
ALTHOUGH GALE FORCE WINDS ARE NOT ANTICIPATED BEHIND THE FRONT...THERE
COULD BE A PERIOD OF 25 TO 30 KT WINDS ON WEDNESDAY. ALSO DUE TO THE
LONG NORTH TO SOUTH FETCH...WAVES ALONG THE SOUTHERN HALF OF THE
LAKE MAY BE IN THE 4 TO 8 FT RANGE. THIS WILL LIKELY PRODUCE SMALL
CRAFT CONDITIONS AGAIN WEDNESDAY AND WEDNESDAY NIGHT.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
