National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KILX 142347
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
647 PM CDT TUE MAY 14 2013

.DISCUSSION...
ISSUED 253 PM CDT TUE MAY 14 2013

MAIN CONCERN THIS FORECAST PACKAGE WILL CONTINUE TO BE TIMING AND
LOCATION OF PCPN THROUGH THE SHORT AND LONG TERM PERIODS.

MODELS REMAIN IN VERY GOOD AGREEMENT WITH OVERALL UPPER LEVEL
PATTERN BEING QUASI-ZONAL WITH A LOW PRESSURE AREA MOVING ACROSS
THE SOUTHERN MO/NORTHERN AR MIDDLE OF THE WEEK. THEN RIDGING WILL
SLOWLY RETURN TO THE PLAINS FOR END OF THE WEEK AND INTO THE
WEEKEND. ON THE SFC...MODELS AGREE WITH TIMING/MOVEMENT AND
LOCATION OF THE FRONT DROPPING INTO THE AREA TOMORROW AFTERNOON
AND REMAINING THERE THROUGH REST OF THE WEEK. MOVING INTO THE
WEEKEND...MODELS SEEM TO DIFFER WITH GFS KEEPING THE FRONT OVER
THE CWA AND THE ECMWF KEEPING THE FRONT WEAK OR WASHING IT OUT.
EARLY NEXT WEEK...MODELS DIFFER QUITE A BIT ON THE SFC FEATURES
AND LOCATIONS. SO OVERALL...CURRENT FORECAST LOOKS GOOD WITH
CURRENT MODEL TRENDS AND ONLY SEE SMALL ADJUSTMENTS NEED IN POPS
AND TEMPS THROUGH THE PERIOD.

SHORT TERM...TONIGHT THROUGH FRIDAY

DRY WEATHER IS EXPECTED THROUGH TOMORROW MORNING AHEAD OF A COLD
FRONT THAT WILL DROP INTO THE AREA TOMORROW MORNING. AS THE FRONT
MOVES INTO THE CWA...IT SHOULD INTERACT WITH LIMITED SFC MOISTURE
TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS FROM TOMORROW
AFTERNOON INTO TOMORROW NIGHT. STRENGTH OF DYNAMICS AND MOISTURE
DO NOT LOOK STRONG ENOUGH FOR SEVERE STORMS...SO JUST EXPECTING
REGULAR THUNDERSTORMS AT THIS TIME. THIS FRONT WILL THEN BECOME
PARALLEL WITH THE MID LEVEL FLOW AND BECOME STATIONARY OVER THE
CWA THROUGH THE REST OF THE WEEK. INITIAL THOUGHTS ARE THAT
SHOWERS AND STORMS ARE LIKELY TOMORROW NIGHT THROUGH THURSDAY
DURING THE TIME WHEN THE CONVERGENCE ALONG THE FRONT WILL BE
STRONGEST. BEYOND THURSDAY...IT IS TOO DIFFICULT TO TELL WHERE
STORMS WILL BE LIKELY SO WILL JUST HAVE CHANCE POPS FOR THUR NIGHT
AND FRIDAY. THIS TYPE OF CONVECTION WILL BE DRIVEN BY MESOSCALE
FEATURES THAT ARE TOO DIFFICULT TO PREDICT 48+ HRS OUT.
HOWEVER...THERE WILL PROBABLY BE SOME BREAKS IN THE PCPN...BUT
UNSURE WHEN.

TEMPS WILL REMAIN ABOVE NORMAL THROUGH THE REST OF THE WEEK WITH
THE WARMEST DAY BEING TOMORROW. CLOUDS AND PCPN WILL KEEP TEMPS
DOWN SOME FOR THUR AND FRI.

LONG TERM...FRIDAY NIGHT THROUGH TUESDAY

THE FRONT WILL REMAIN OVER THE AREA AT THE BEGINNING OF THE
WEEKEND BUT SHOULD BEGIN TO MOVE BACK NORTH AS A WARM
FRONT...LIFTING NORTH OF THE CWA FOR SAT NIGHT. THIS APPEARS TO BE
THE BEST CHANCE FOR NO PCPN AT THIS TIME. HOWEVER...THE MAIN
SYSTEM WILL JUST BE TO THE WEST OF THE AREA AND PCPN WILL BEGIN TO
RETURN TO THE CWA SUNDAY AND BECOME LIKELY FOR SUNDAY NIGHT IN THE
WEST. THE RISK OF SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
EARLY NEXT WEEK AS THE MAIN SYSTEM IS FORECAST TO MOVE THROUGH THE
AREA. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY FOR MONDAY
NIGHT IN THE EAST BUT THEN DECREASE INTO THE CHC CATEGORY FOR
TUESDAY. IF THE ECMWF IS CORRECT...DRY WEATHER IS ON THE HORIZON.

TEMPS WILL REMAIN ABOVE NORMAL WITH SUN BEING THE WARMEST WITH THE
CWA BEING IN THE WARM SECTOR.



&&

.AVIATION...
ISSUED 647 PM CDT TUE MAY 14 2013

GUSTY SOUTHWESTERLY WINDS WILL SUBSIDE TO BETWEEN 10 AND 15KT OVER
THE NEXT COUPLE OF HOURS...THEN WILL CONTINUE THROUGH THE NIGHT.
NAM SHOWS A 50-55KT LOW-LEVEL JET DEVELOPING OVERNIGHT...SO HAVE
INCLUDED WIND SHEAR AT ALL TERMINALS AFTER THE 03-05Z TIME FRAME.
WEAK COLD FRONT CURRENTLY POSITIONED ACROSS WISCONSIN INTO IOWA
WILL SAG SOUTHWARD ON WEDNESDAY. MODELS ARE SHOWING THIS BOUNDARY
SETTLING INTO CENTRAL ILLINOIS...THEN BECOMING NEARLY STATIONARY
BY WEDNESDAY AFTERNOON/EVENING. BASED ON NAM AND LOCAL WRF
MODELS...HAVE VEERED WINDS TO NORTHWESTERLY AT BOTH KPIA AND KBMI
BY MIDDAY. FURTHER SOUTH...HAVE GONE WITH LIGHT/VARIABLE WINDS AT
THE REMAINING TAF SITES WITH THE FRONT IN THE VICINITY. ALL MODELS
TRY TO DEVELOP SCATTERED CONVECTION ALONG THE BOUNDARY WEDNESDAY
AFTERNOON/EVENING...HOWEVER FORECAST SOUNDINGS REMAIN QUITE DRY.
WILL THEREFORE ONLY MENTION VCTS AT THE I-72 TERMINALS AFTER 21Z.

BARNES
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$