Severe Thunderstorm Warning 1, NWS Detroit, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
339 PM EST WED MAR 15 2000

MAIN FORECAST CHALLENGES THIS AFTERNOON REVOLVE AROUND CLOUD COVER
AND THE POTENTIAL FOR ANY LAKE EFFECT TONIGHT.

AS PER VISIBLE IMAGERY...CLOUDS FROM THE LOW OVER KY/TN HANGING
TOUGH OVER THE SOUTHERN ONE-THIRD TO ONE-HALF OF THE CWA AT THIS
TIME...WITH LAKE EFFECT CLOUDS HOLDING SWAY FURTHER NORTH. THE
MODELS ARE ALL PRETTY CONSISTENT IN DRIVING THE SYSTEM CLOUDS SOUTH
AND EAST OF THE CWA THIS EVENING...AND BRINGING LOTS OF DRY AIR IN
FROM THE NORTH OVERNIGHT AS HIGH PRESSURE BUILDS IN. THE MODELS ALSO
HAVE A STRONG SHORTWAVE ENTERING INTO THE PICTURE OVERNIGHT...SOME
HIGH CLOUDS CAN CURRENTLY BE SEEN OVER MN/WI IN ASSOCIATION WITH
THIS FEATURE. AT THIS POINT...WITH PLENTIFUL DRY AIR WORKING IN
OVERNIGHT...CANT SEE MUCH MORE THAN A FEW HIGH CLOUDS WITH THIS
FEATURE. THEREFORE...WILL GENERALLY START OUT THE FIRST PERIOD
MOSTLY CLOUDY/CLOUDY...FOLLOWED BY BECOMING PARTLY CLOUDY OVERNIGHT
AS THE DRY AIR MOVES ON IN.

AS FOR LAKE EFFECT...VISIBLE IMAGERY STILL SHOWS BANDS GOING PRETTY
WELL ATTM...THOUGH THEY ARE PROBABLY FAIRLY SHALLOW CONSIDERING
NOTHING IS SHOWING UP ON OUR RADAR. SURFACE OBS NOT INDICATING MUCH
FALLING FROM THE LAKE CLOUDS ATTM EITHER...AND WOULDNT EXPECT THAT
CONSIDERING INVERSION HEIGHTS ARE CURRENTLY AROUND 900MB. THE
INVERSION WILL GRADUALLY LIFT TO AROUND 850MB OVERNIGHT...AND 850
TEMPS WILL BE ON THE FALL. HOWEVER...THE COLDEST AIR DOESNT GET IN
UNTIL LATE TONIGHT...THE FLOW WILL ALSO BE GOING ANTICYCLONIC...AND
AS ALREADY MENTIONED...DRY AIR WILL BE ADVECTING IN ON N/NE
FLOW...SO I DONT EXPECT MUCH MORE THAN SOME SCATTERED -SHSN OFF OF
SAGINAW BAY...WHERE BANDING IS BEST AT THIS TIME...AND FLURRIES UP
IN THE THUMB. ANY ACTIVITY SHOULD PRIMARILY OCCUR THE FIRST PART OF
THE NIGHT...AS CONDITIONS BECOME INCREASINGLY UNFAVORABLE AS TIME
PROGRESSES. AS THIS IS THE CASE...BECOMING PARTLY CLOUDY WORDING
SHOULD WORK UP THE SAGINAW VALLEY/THUMB AREAS AS WELL.

REST OF FORECAST IS THEN PRETTY STRAIGHTFORWARD. CANADIAN HIGH
PRESSURE WILL BUILD IN DURING FRIDAY...AND COMBINED WITH STRONG NVA
IN THE WAKE OF THE DEPARTING SHORTWAVE AND LOTS OF DRY AIR...CLOUDS
SHOULDNT BE A PROBLEM...EVEN WITH THE COLD 850 TEMPS. WILL CALL THINGS
MOSTLY SUNNY...PRIMARILY TO ACCOUNT FOR ANY LEFTOVER MORNING
CLOUDINESS. FRIDAY NIGHT SHOULD BE CLEAR AND COLD WITH THE HIGH
OVERHEAD AND LIGHT WINDS...ALLOWING FOR GOOD RADIATIONAL COOLING.
SATURDAY WILL START OUT SUNNY...WITH INCREASING CLOUDS IN THE
AFTERNOON AHEAD OF THE NEXT SYSTEM. AS FOR TEMPERATURES...WILL
GENERALLY STICK CLOSE TO GUIDANCE VALUES AS THESE LOOK
REASONABLE...THOUGH WILL CUT BACK TEMPS A BIT UP NORTH FRIDAY NIGHT
DUE TO RIDGE HOLDING LONGEST THERE.

AS FOR THE EXTENDED...A SIGNIFICANT CHANGE IN THE MRF SOLUTION FROM
YESTERDAYS RUN. THE MRF NO LONGER DEVELOPS A CUTOFF OVER THE
SOUTHWESTERN STATES FOR THE UPCOMING WEEKEND...WHICH IS MUCH MORE IN
LINE WITH YESTERDAYS AND TODAYS VERSIONS OF THE LOCALLY RUN ETA
EXTENDED (ETA-XX) PROG. AS A RESULT...MORE SHORTWAVE ENERGY
TRANSLATES EAST INTO THE GREAT LAKES REGION FOR THE SATURDAY
NIGHT/SUNDAY TIME FRAME...RESULTING IN A MORE PRONOUNCED NORTHERN
STREAM SURFACE LOW...AGAIN MUCH LIKE THE ETA-XX. WILL THUS UP POPS
AND THROW IN CHANCE WORDING FOR THE SAT NIGHT/SUN. AS FOR
TYPE...WILL GO WITH JUST A CHANCE OF SNOW SAT NIGHT AS 1000-850
THICKNESSES ARE SUB-1300 ACROSS THE ENTIRE CWA...AND CHANCE RAIN OR
SNOW FOR SUN TO COVER THE POSSIBILITY OF ANY EARLY DAYTIME WHITE
STUFF...EVEN THOUGH THICKNESSES RISE ABOVE CRITICAL LEVELS DURING
THE DAY.

BEYOND SUNDAY...THE FIRST TWO DAYS OF THE NEW WEEK CONTINUE TO BE DRY
AT THIS TIME...AS BOTH THE MRF AND ETA-XX KEEP HIGH PRESSURE IN
CONTROL OVER SOUTHEAST MICHIGAN AND KEEP LOW PRESSURE CONFINED TO
THE SOUTHEASTERN US. ONE DIFFERENCE THOUGH...ESPECIALLY WITH THE
MRF...IS THAT DEEP SOUTHWEST FLOW NEVER MATERIALIZES FOR THE FIRST
PART OF THE WEEK...IN LARGE PART DUE TO THE CIRCULATION AROUND THE
SOUTHEASTERN US LOW...WITH THE MRF KEEPING US IN A MOIST EAST TO
SOUTHEAST FLOW THRU WED. THEREFORE...I WOULD EXPECT TEMPS TO BE
COOLER THAN DEPICTED BY YESTERDAYS RUN...AND WILL THUS TREND TEMPS
DOWN A BIT IN LATER PERIODS. NEXT SYSTEM TO AFFECT AREA WILL MOVE IN
FOR TUE NIGHT/WED AS PER THE ETA XX/CANADIAN GEM...SO WILL KEEP IN
CHANCE OF RAIN SHOWERS FOR WED AS PER GOING EXTENDED.

.DTX...NONE.

ROZBICKI

MIZ047>049-053>055-060>063-068>070-075-076-082-083-160500-

SEVERE WEATHER OUTLOOK FOR SOUTHEAST LOWER MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
502 PM EST WED MAR 15 2000

...SEVERE WEATHER POTENTIAL STATEMENT FOR SOUTHEAST MICHIGAN...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

AN ISOLATED THUNDERSTORM OR TWO IS POSSIBLE ACROSS THE SAGINAW
VALLEY AND NORTHERN THUMB THIS EVENING. ANY THUNDERSTORM THAT
DEVELOPS IS NOT EXPECTED TO BECOME SEVERE AND SPOTTER ACTIVATION IS
NOT ANTICIPATED.

A STRONG COLD FRONT WILL SWEEP ACROSS SOUTHEAST MICHIGAN TONIGHT.
THERE MAY BE ENOUGH INSTABILITY TO PRODUCE A FEW THUNDERSTORMS
ACROSS THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE MIDNIGHT AS THE
FRONT PASSES THROUGH THAT PORTION OF SOUTHEAST MICHIGAN.
HOWEVER...ATMOSPHERIC CONDITIONS WILL NOT BE CONDUCIVE FOR SEVERE
THUNDERSTORMS. THE REMAINDER OF SOUTHEAST MICHIGAN WILL SEE THE FRONT
PASS THROUGH DURING THE OVERNIGHT HOURS. IT DOES NOT APPEAR THAT
THERE WILL BE SUFFICIENT INSTABILITY TO SUPPORT ANY THUNDERSTORMS AT
THAT TIME.

ANY THUNDERSTORM THAT DOES DEVELOP COULD PRODUCE BRIEFLY HEAVY
RAIN...OCCASIONAL LIGHTNING STRIKES...WIND GUSTS TO 40 MPH...AND PEA
SIZE HAIL. MOVEMENT OF THESE STORMS WOULD BE NORTHEAST AT ABOUT 40
MPH.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL MEDIA
OUTLET...FOR THE LATEST WEATHER INFORMATION.

JW

MIZ047>049-053>055-060>063-068>070-075-076-082-083-160500-

SEVERE WEATHER OUTLOOK FOR SOUTHEAST LOWER MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
535 PM EST WED MAR 15 2000

...SEVERE WEATHER POTENTIAL STATEMENT FOR SOUTHEAST MICHIGAN...

DISPATCHERS...PLEASE NOTIFY YOUR EMERGENCY MANAGERS IMMEDIATELY.

AN ISOLATED THUNDERSTORM OR TWO IS POSSIBLE ACROSS SOUTHEAST
MICHIGAN THIS EVENING. ANY THUNDERSTORM THAT DEVELOPS IS NOT
EXPECTED TO BECOME SEVERE AND SPOTTER ACTIVATION IS NOT ANTICIPATED.

A STRONG COLD FRONT WILL SWEEP ACROSS SOUTHEAST MICHIGAN TONIGHT.
THERE MAY BE ENOUGH INSTABILITY TO PRODUCE A FEW THUNDERSTORMS
BEFORE MIDNIGHT...ESPECIALLY ACROSS THE SAGINAW VALLEY AND NORTHERN
THUMB AS THE FRONT PASSES THROUGH THAT PORTION OF SOUTHEAST
MICHIGAN. HOWEVER...ATMOSPHERIC CONDITIONS WILL NOT BE CONDUCIVE FOR
SEVERE THUNDERSTORMS. THE REMAINDER OF SOUTHEAST MICHIGAN WILL SEE
THE FRONT PASS THROUGH DURING THE OVERNIGHT HOURS. IT DOES NOT
APPEAR THAT THERE WILL BE SUFFICIENT INSTABILITY TO SUPPORT ANY
THUNDERSTORMS WITH THE PASSAGE OF THE FRONT AT THAT TIME.

ANY THUNDERSTORM THAT DOES DEVELOP COULD PRODUCE BRIEFLY HEAVY
RAIN...OCCASIONAL LIGHTNING STRIKES...WIND GUSTS TO 40 MPH...AND PEA
SIZE HAIL. MOVEMENT OF THESE STORMS WOULD BE NORTHEAST AT ABOUT 40
MPH.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL MEDIA
OUTLET...FOR THE LATEST WEATHER INFORMATION.

JW