AREA FORECAST DISCUSSION
NWS CHICAGO IL
AFDCHI 303 AM CST WED MAR 15 2000
120+ KNOT JET DIVING INTO PAC NW WILL RESULT IN AMPLIFICATION OF
UPPER FLOW TODAY...CARVING TROF OVER THE ROCKIES. MID LEVEL SHORT
WAVE ENERGY OVER WYOMING/WESTERN DAKOTAS RESULTING IN SURFACE LOW
DEVELOPMENT ALONG NEARLY STATIONARY ARCTIC BOUNDRY VCNTY SE SOUTH
DAKOTA. MODELS IN MUCH BETTER AGREEMENT THIS MORNING WITH
PROGRESSION NEXT 48 HOURS...AS LOW MOVES INTO NORTHERN LOWER
MICHIGAN AHEAD OF SHARPENING MID LEVEL TROF BY THIS EVENING. ARCTIC
AIR PLUNGING SOUTH BEHIND THIS SYSTEM WILL SWEEP TRAILING SURFACE
COLD FRONT ACROSS NORTHERN ILLINOIS AND NORTHWEST INDIANA THIS
AFTERNOON AND EVENING.
STILL A FEW LINGERING LIGHT SHOWERS FROM AROUND PEORIA INTO
SOUTHEAST SIDE OF CHICAGO AREA AT THIS HOUR. THIS OCCURING IN AREA
OF LO LVL WARM ADVECTION AND MOISTURE CONVERGENCE. MODELS DO
DIMINISH THESE SHOWERS EARLY THIS MORNING...BUT WILL LIKELY HAVE TO
INCLUDE SOME LIGHT SHOWERS OR SPRINKLES FOR SOUTHERN SECTIONS OF
FORECAST AREA EARLY THIS MORNING. PRECIPITATION THREAT THEN SHIFTS
TO AFTERNOON AS SURFACE FRONT APPROACHES. GOOD MOISTURE CONVERGENCE
ALONG AND AHEAD OF SURFACE BOUNDARY. WILL CONTIUNE LIKELY POPS AND
METNION OF THUNDER...AS SOME WEAK INSTABILITY PRESENT. MAY SEE SOME
SHOWERS LINGER INTO THURSDAY MORNING...WITH 1000-850 THICKNESS
DROPPING BELOW 1300 METERS COULD SEE SOME SNOW SHOWERS...ESPECIALLY
NORTHERN SECTIONS.
FAN/FWC GUIDANCE HIGHS TODAY IN THE MID-UPPER 50S...AND THIS LOOKS
GOOD GIVEN AMOUNT OF CLOUD COVER TODAY. ACARS SOUNDINGS SUGGEST THIS
IN THE BALLPARK...SHOWING ABOUT +4 DEG C AT 900 MB. MOS NUMBERS IN
GOOD AGREEMENT THROUGH REST OF FORECAST AND ACCEPTED.
.CHI...NONE.
RATZER