AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
606 PM CDT THU MAY 23 2013
.DISCUSSION...
ISSUED 259 PM CDT THU MAY 23 2013
COOLER THAN NORMAL AIR FILTERING INTO THE MIDWEST BEHIND THE FRONT
WILL HELP KEEP TEMPS DOWN TONIGHT...AND MAINTAIN A BELOW AVERAGE
MAX TEMP FOR THE NEXT COUPLE OF DAYS SLIDING INTO THE HOLIDAY
WEEKEND. AS A RIDGE BUILDS OVER THE CENTER OF THE CONUS AT 500
MB...A PROLONGED PD OF POPS AND PRECIP WILL KICK IN AS A SERIES OF
WAVES TOP THE RIDGE AND DIVE INTO THE MIDWEST STARTING ON
SATURDAY. MODELS ARE IN PRETTY DECENT AGREEMENT THROUGH SUNDAY
WITH SHOWERS OFF AND ON ASSOCIATED WITH THE RIDGE WAVES.
HOWEVER...AFTER SUNDAY THE MODELS DIVERGE QUITE A BIT WITH THE
WAVE PATTERN AND PRECIP CHANCES...THOUGH BOTH THE GFS AND THE
ECMWF BEGIN A WARMING TREND AS THE WARM AIR TRAPPED UNDER THE
RIDGE IN THE MIDLEVELS MOVES INTO THE MIDWEST.
SHORT TERM...TONIGHT AND TOMORROW...
COOL TEMPERATURES REMAIN IN PLACE FOR THE OVERNIGHT WITH EFFICIENT
RADIATIONAL COOLING AS THE SKIES CLEAR FROM A RELATIVELY CLOUDY
DAY. FOG NOT ANTICIPATED AS THE DRY AIR WORKING INTO THE AREA FROM
THE NORTH SHOULD KEEP THE RH DOWN A BIT. CONCERN HOWEVER...FOR THE
TIME DISPLACEMENT OF THE TEMP DROP AND A SLOWER TIMING ON THE DRY
AIR AS SO MUCH MOISTURE HAS BEEN TRAPPED IN THE BOUNDARY LAYER
WITH MINIMAL MIXING TODAY. WILL HAVE TO WATCH TRENDS VERY CLOSELY
FOR T/TD WITH CLEARING AS THE SUN SETS. TOMORROW WILL BE DRY AND
CLEAR...AND THOUGH STILL BELOW NORMAL...A FEW DEGREES WARMER THAN
TODAY. OVERNIGHT...MAINLY AFTER MIDNIGHT FRI NIGHT/SAT
MORNING...AN APPROACHING WAVE WILL BRING THE FIRST PRECIP THREAT
EARLY SATURDAY MORNING.
LONG TERM...SATURDAY THROUGH WEDNESDAY...
SATURDAY AND SUNDAY BOTH SHOWERY WITH THREAT OF THUNDER
THOUGH WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED. BETWEEN THE
SHOWERS AND THE COOLER TEMPERATURES...HOLIDAY WEEKEND ACTIVITIES
MAY BE CURTAILED SOMEWHAT OUTDOORS. MONDAY WILL START A BIT MORE
OF A WARMING TREND AS THE HEAT BUILDUP UNDER THE RIDGE SHIFTS
EASTWARD. WHEREAS THE ECMWF KEEPS THE RIDGE INTACT AND SHIFTS IT
EASTWARD...THE GFS BREAKS DOWN THE EASTERN SIDE OF THE RIDGE AND
DEEPENS THE TROF OVER THE WEST COAST...SHIFTING TO A MORE
PROGRESSIVE SWRLY FLOW. EITHER WAY...SHOWER CHANCES WILL CONTINUE
WITHIN THE WARMING TREND...BUT THE DYNAMICS OF THE SITUATION MAY
SHIFT SIGNIFICANTLY BEYOND MONDAY INTO THE FIRST HALF OF THE WEEK.
&&
.AVIATION...
ISSUED 602 PM CDT THU MAY 23 2013
EXCEPT FOR A BRIEF PERIOD OF MVFR CIGS THIS EVENING...VFR
CONDITIONS ARE EXPECTED THRU FRIDAY. BACKEDGE OF CLOUD SHIELD
PUSHING ACRS OUR NORTHERN AREAS AT THIS TIME AND WE SHOULD
SEE THAT PROGRESS SOUTH THIS EVENING. BASES OF THE CIGS FOR
A TIME THIS EVENING WILL RANGE FROM 2500-3500 FEET...AND THEN
SHOULD BEGIN TO CLEAR OUT BY 03Z AT ALL SITES. SFC WINDS WILL
DIMINISH QUICKLY THIS EVENING OUT OF A NNE DIRECTION AS HIGH
PRESSURE SETTLES IN FROM THE NORTH. WINDS SHOULD GRADUALLY
VEER MORE INTO A NORTHEAST TO EAST DIRECTION ON FRIDAY WITH
SPEEDS OF 10 KTS OR LESS.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
