AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 355 PM CDT TUE APR 26 2011 ...SIGNIFICANT SEVERE WEATHER EVENT CURRENTLY UNFOLDING...TIME FRAME IS FOR TONIGHT INTO WEDNESDAY... .DISCUSSION...MAJOR SEVERE WEATHER OUTBREAK READY TO UNFOLD FROM THE ARKLATEX THROUGH OUR FORECAST AREA INTO AL AND TN VALLEY TONIGHT INTO WED. THIS EVENT WILL BE THE FOCUS OF THIS FORECAST FOR THE NEXT 24HRS THEN A SHIFT TO COOLER AND DRIER CONDITIONS INTO THE WEEKEND. ACROSS THE AREA TODAY...THE ATMOSPHERE IS QUICKLY RESPONDING AND RECOVERING FROM THE MORNING STORM COMPLEX. BASED OFF VAPOR IMAGERY...SEVERAL DISTURBANCES ARE NOTED IN THE MEAN UPPER TROUGH. IT IS THESE FEATURES...ALONG WITH THE MAIN DIGGING TROUGH...THAT IS CAUSING SURFACE PRESSURES TO LOWER ACROSS TX WHICH IS IN TURN ALLOWING PRESSURES TO FALL OVER OUR REGION. FORECAST MODELS SEEM TO BEING WELL WITH THE ABOVE FEATURES I MENTIONED AND SHOW THE RAPID RESPONSE TO THE WIND FIELDS AND RECOVERY OF THE ATMOSPHERE. TAKING THE VARIOUS MODEL GUIDANCE ALONG WITH HI-RES OUTPUT...MULTIPLE ROUNDS OF STORMS APPEAR POSSIBLE WITH THE VARIOUS EMBEDDED WAVES FROM LATE THIS AFTERNOON...EVENING/OVERNIGHT AND THEN ON WED. THE AREAS UNDER THE GREATEST RISK HAVE NOT CHANGED. LOCATIONS NORTH OF I-20 CONTINUE TO HAVE THE GREATEST RISK WITH AREAS ALONG AND S OF I-20 HAVING A MORE ISOLATED RISK. THE SOUTHERN HALF WILL HAVE TO COMPETE WITH LOW/MID LEVEL CAPPING AND ALL INDICATIONS ARE THAT IT WILL BE TOUGH TO BREAK THE CAP EVEN IN THE FACE SUCH INTENSE FORCING. HOWEVER...IF ANYTHING CAN DEVELOP...CONDITIONS WILL BE VERY FAVORABLE FOR HIGH END SEVERE STORMS. THE NORTHERN HALF WILL LIKELY HAVE SOME CAP...BUT IT WON'T BE AS STRONG AND THE DEPTH OF MOISTURE AND ASCENT WILL ALLOW FOR MULTIPLE ROUNDS OF STORMS. THE REPETITIVE EXPECTATION OF STORMS WILL LIKELY LEAD TO LOCALLY HEAVY RAINS ACROSS THE NORTH WITH 3-6 INCH TOTALS POSSIBLE. SOME HIGHER AMOUNTS COULD ALSO OCCUR. DUE TO THIS...HAVE EXPANDED THE AREA OF THE FLASH FLOOD WATCH. THE SEVERITY OF THIS EVENT WILL ULTIMATELY COME DOWN TO STORM MODE (SUPERCELL VS SQUALL LINE). AT THIS TIME...IT SEEMS AS THE AREA WILL SEE A MIXTURE OF BOTH THROUGH THIS EVENT. WITH ANY SUPERCELL STORM...THERE WILL EXIST THE POSSIBILITY OF LONG TRACK STRONG TORNADOES....VERY LARGE HAIL AND DAMAGING WINDS TO 80 MPH. AS FOR ANY LINE SEGMENT...DAMAGING WINDS TO 80 MPH WILL BE THE PRIMARY RISK WITH HAIL AND TORNADOES ALSO A SUBSTANTIAL RISK. EITHER WAY AND WHICH EVER MODE OCCURS...THE RISK FOR SIGNIFICANT SEVERE WEATHER IS POSSIBLE. AS FOR TIMING...THERE IS NO SPECIFIC TIME...JUST A LARGE WINDOW OF FAVORABLE CONDITIONS ACROSS THE N HALF FROM NOW THROUGH WED AFTERNOON. I WOULD SAY THAT THE SE PORTION OF THE AREA WILL WAIT UNTIL AT LEAST MID/LATE MORNING AND DURING WED AFTERNOON. I DO FEEL CONFIDENT THAT THINGS WILL PUSH EAST AND EXIT THE AREA BY 7 PM WED. IN ADDITION TO ALL THE SEVERE WEATHER...SURFACE WINDS WILL INCREASE OVERNIGHT AND BECOME QUITE GUSTY. THE STRONGEST WINDS LOOK TO OCCUR ON WED AS THE AREA WARMS AND MIXES DOWN THE INTENSE WINDS JUST OFF THE SURFACE. ADDITIONALLY...WHEN THE DRY LINE MOVES ACROSS THE W/NW AREAS...DEEPER MIXING WILL OCCUR AND HELP TO BRING DOWN WINDS OF 40-50 MPH. FOR NOW...HAVE ISSUED A WIND ADV FOR ALL OF THE AREA. PORTIONS OF THE W/NW MAY NEED A HIGH WIND WARNING. THIS WILL BE LOOKED AT CLOSER IN LATER FORECASTS AND UPDATED AS NEEDED. BEYOND 8 PM TOMORROW...CONDITIONS WILL BE QUIET WITH COOLER AND MORE SEASONAL CONDITIONS EXPECTED. NEXT REAL CHANCE AT PRECIP LOOKS TO WAIT UNTIL SUN OR MON.
***DO NOT USE THIS WEBSITE AS YOUR SOLE SOURCE OF WEATHER INFORMATION, ESPECIALLY WATCHES AND WARNINGS. THIS WEBSITE DELIVERS FOCUSED INFORMATION FOR A SPECIFIC GEOGRAPHIC AREA AND IS NOT INTENDED TO PROVIDE TIMELY WEATHER WARNING INFORMATION***
No comments:
Post a Comment