Archive for December 2008
TORNADO WATCH NUMBER 963
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CST SAT DEC 27 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
NORTHEAST ILLINOIS
NORTHWEST INDIANA
LAKE MICHIGAN
EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 1230 PM UNTIL
700 PM CST.
TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 20 MILES NORTHWEST OF
MARSEILLES ILLINOIS TO 15 MILES SOUTH OF VALPARAISO INDIANA. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU3).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...CONTINUE...WW 960...WW 961...WW 962...
DISCUSSION...NARROW LINE OF LOW-TOPPED STORMS CONTINUES TO RACE NEWD
ACROSS CENTRAL IL AND WILL LIKELY MOVE ACROSS AT LEAST THE SRN HALF
OF THE CHICAGO METRO AND INTO FAR NWRN IND OVER THE NEXT COUPLE
HOURS. WIND DAMAGE WILL BE PRIMARY SEVERE THREAT FROM THE
STRONGLY-FORCED LINE...ALTHOUGH EXTREME LOW LEVEL SHEAR AND STRONG
PRESSURE FALLS AT THE SURFACE MAY SUPPORT A RISK OF ISOLATED
TORNADOES.
...WINTER STORM TO AFFECT THE AREA THURSDAY EVENING THROUGH EARLY
FRIDAY MORNING...
.ANOTHER ROUND OF WINTER WEATHER IS EXPECTED TO IMPACT THE
MIDWEST BEGINNING LATE THIS AFTERNOON AND CONTINUING INTO FRIDAY
MORNING. THIS STORM SYSTEM WILL BRING AN EXTENDED PERIOD OF
SNOW...FREEZING RAIN AND SLEET TO NORTHERN ILLINOIS AND
NORTHWESTERN INDIANA. LATEST GUIDANCE SUGGESTS THIS STORM
SYSTEM...NOW MOVING ACROSS SOUTHERN CALIFORNIA...WILL TRACK A BIT
FURTHER SOUTH...TAKING A PATH FROM WESTERN KANSAS THURSDAY
EVENING...TO JUST NORTH OF ST. LOUIS EARLY FRIDAY MORNING...THEN
TO WESTERN OHIO BY MIDDAY FRIDAY. THIS PATH WOULD SUGGEST HEAVY
SNOW ACROSS EXTREME NORTHERN ILLINOIS WITH A MIX OF SNOW...SLEET
AND FREEZING RAIN ALONG THE INTERSTATE 80 CORRIDOR...AND
SIGNIFICANT FREEZING RAIN FROM NEAR PONTIAC TO KANKAKEE TO
RENSSELAER AND POINTS SOUTHWARD.
NORTH OF INTERSTATE 88 PRECIPITATION IS EXPECTED TO BE MAINLY
SNOW...WHICH MAY ACCUMULATE TO AROUND A FOOT NEAR THE WISCONSIN
STATE LINE.
TO THE SOUTH...WHERE FREEZING RAIN IS EXPECTED...TOTAL ICE
ACCUMULATION MAY EXCEED ONE HALF INCH IN SOME LOCATIONS. ICE
ACCUMULATION OF THIS MAGNITUDE WILL CAUSE DAMAGE TO POWER LINES
AND TREE LIMBS. TRAVEL WILL BE TREACHEROUS ON MANY AREA ROADS.
...WINTER STORM WATCH IN EFFECT FROM 3 PM THURSDAY TO 12 NOON FRIDAY...
.ANOTHER ROUND OF WINTER WEATHER IS EXPECTED TO IMPACT THE MIDWEST
THURSDAY THROUGH FRIDAY MORNING. THIS STORM SYSTEM WILL BRING AN
EXTENDED PERIOD OF FREEZING RAIN AND SLEET TO NORTHERN ILLINOIS
AND NORTHWESTERN INDIANA. SIGNIFICANT ICE ACCUMULATION IS EXPECTED
WITH THIS STORM SYSTEM. THE FAR NORTHERN LOCATIONS NEAR THE
WISCONSIN BORDER WILL INITIALLY SEE A MIX OF SNOW AND SLEET BEFORE
CHANGING OVER TO SLEET AND FREEZING RAIN. THE FAR SOUTHEASTERN
LOCATIONS OF EAST CENTRAL ILLINOIS AND WEST CENTRAL INDIANA WILL
SEE THE FREEZING RAIN CHANGE OVER TO ALL LIQUID FOR A PERIOD EARLY
FRIDAY MORNING AS WARMER AIR SURGES NORTH AHEAD OF AN APPROACHING
COLD FRONT. AS THE COLD FRONT PUSHES THROUGH THE REGION FRIDAY
MORNING...THE PRECIPITATION WILL CHANGE OVER TO LIGHT SNOW.
TOTAL ICE ACCUMULATION MAY EXCEED ONE HALF INCH IN SOME LOCATIONS.
ICE ACCUMULATION OF THIS MAGNITUDE WILL CAUSE DAMAGE TO POWER
LINES AND TREE LIMBS. TRAVEL WILL BE TREACHEROUS ON MANY AREA
ROADS.
...HAZARDOUS WINTER CONDITIONS ENTERING REGION... .A STRONG COLD FRONT CURRENTLY ENTERING WESTERN ILLINOIS WILL SHARPLY DROP TEMPERATURES ACROSS THE REGION TONIGHT FROM THE 50S INTO THE 20S IN A MATTER OF HOURS. AFTER THE FRONT PASSES AND THE COLDER AIR COMES INTO THE REGION...A BAND OF FREEZING RAIN IS EXPECTED TO COME THROUGH LEAVING A SMALL ACCUMULATION OF ICE ON BELOW FREEZING SURFACES. WITH A BRIEF PERIOD OF RAIN AND THEN THE FREEZING RAIN WITH SURFACE TEMPERATURES WELL BELOW FREEZING...ROADS ARE EXPECTED TO BECOME ICY AND DANGEROUS. WINDS BEHIND THE FRONT ARE ALSO EXPECTED TO REMAIN STRONG AND GUSTY UP TO 40 MPH.
