490
FXUS64 KMOB 190449 AAA
AFDMOB
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MOBILE AL
1149 PM CDT THU APR 18 2019
DISCUSSION
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION
06Z ISSUANCE...EXPECT MVFR TO IFR CIGS THROUGH ABOUT 19.09Z
THEN MOSTLY MVFR CIGS THROUGH 20.00Z. LOWER CIGS AND VISIBILITIES
IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH ABOUT
19.09Z THEN MOSTLY IN LOW CIGS WITH SCATTERED SHOWERS THROUGH
20.00Z, CLEARING THROUGH 20.06Z. WINDS WILL BE SOUTHEAST TO SOUTH
AT 15 TO 25 KNOTS WITH GUSTS TO 30 KNOTS THROUGH ABOUT 19.09Z
THEN SLOWLY SHIFTING WEST TO NORTHWEST THROUGH AT 15 TO 20 KNOTS
WITH GUSTS TO 30 KNOTS THROUGH 20.00Z THEN SLOWLY DIMINISHING
THROUGH 20.06Z. 32/EE
PREV DISCUSSION
/ISSUED 1115 PM CDT THU APR 18 2019/
DISCUSSION...SEE UPDATED INFORMATION FOR LAND AREAS BELOW.
UPDATE...HAVE UPDATED FOR THE EXPIRATION OF TORNADO WATCH 84.
MADE ADDITIONAL MAINLY MINOR ADJUSTMENTS FOR THE REMAINDER OF THE
NIGHT. /29
PREV DISCUSSION... /ISSUED 914 PM CDT THU APR 18 2019/
DISCUSSION...SEE UPDATED INFORMATION FOR LAND AREAS BELOW.
UPDATE...THE TORNADO WATCH HAS BEEN CANCELED FOR CHOCTAW COUNTY
IN AL. THE TORNADO WATCH HAS EXPIRED FOR THE FOLLOWING COUNTIES IN
SOUTHEAST MS...STONE...GEORGE...GREENE...WAYNE AND PERRY. 32/EE
PREV DISCUSSION... /ISSUED 838 PM CDT THU APR 18 2019/
DISCUSSION...SEE UPDATED INFORMATION FOR LAND AREAS BELOW.
UPDATE...THUNDERSTORMS CONTINUE TO FIRE ALONG A WIDE BAND
MOVING EASTWARD OVER MIDDLE SECTIONS OF THE FORECAST AREA. HAVE
HAD SEVERAL REPORTS OF TREES AND POWER LINES DOWN ACROSS THE
WESTERN HALF OF THE FORECAST AREA MOSTLY FROM BOWING SEGMENTS
ALONG THE LINE WITH MAYBE A FEW SHORT LIVED TORNADOES. EXPECT
THIS LINE OF STORMS TO CONTINUE MOVING EAST ACROSS THE EASTERN
HALF OF THE FORECAST AREA THIS EVENING LIKELY LEADING TO MORE WIND
DAMAGE ESPECIALLY BEFORE IT CLEARS TO THE EAST A FEW HOURS AFTER
MIDNIGHT. TO THE WEST ANOTHER LINE OF THUNDERSTORMS HAS DEVELOPED
OVER LA STRETCHING INTO MS MOVING EAST LIKELY MOVING INTO WESTERN
SECTIONS OF THE FORECAST AREA IN THE NEXT HOUR OR SO. NEAR THE
SURFACE A WELL DEFINED MESO LOW HAS DEVELOPED NEAR THE AL/MS
BORDER THIS EVENING PROGGED TO SHIFT NORTH NORTHEAST THROUGH THE
REMAINDER OF TONIGHT. FURTHER EAST REASONABLE INSTABILITY IS STILL
NOTED WITH MIXED LAYER CAPES GENERALLY AROUND 1000 J/KG OVER THE
NORTHERN HALF OF THE FORECAST AREA AND ABOUT 1500 J/KG FURTHER
SOUTH TO THE COAST COMBINED WITH VERY HIGH VERTICAL SHEAR IN THE
BOUNDARY LAYER LIKELY LEADING TO MORE BOWING SEGMENTS AND SHORT
LIVE TORNADOES BEFORE THE MAIN BAND MOVES OFF TO THE EAST 2 TO 3
HOURS AFTER MIDNIGHT. FOR THE SECOND ROUND OF STORMS WE WILL
LIKELY KEEP THE SEVERE THREAT UP FOR NOW THOUGH WE DO SEE WINDS
VEERING TO THE SW OVER MS AND LA WHICH SHOULD LOWER THE THREAT FOR
TORNADOES THOUGH MAINTAINING THREAT FOR THE DAMAGING STRAIGHT
LINE WINDS FOR NOW. STAY TUNED FOR FURTHER UPDATES AS THIS NEXT
SYSTEM CONTINUOUS APPROACH FROM THE WEST. 32/EE
PREV DISCUSSION... /ISSUED 657 PM CDT THU APR 18 2019/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...
00Z ISSUANCE...EXPECT MVFR TO IFR CIGS THROUGH ABOUT 19.09Z
THEN MOSTLY MVFR CIGS THROUGH 20.00Z. LOWER CIGS AND VISIBILITIES
IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH ABOUT
19.09Z THEN MOSTLY IN LOW CIGS WITH SCATTERED SHOWERS THROUGH
20.00Z. WINDS WILL BE SOUTHEAST AT 15 TO 25 KNOTS WITH GUSTS TO
40 KNOTS THROUGH ABOUT 19.04Z SHIFTING SOUTH THEN SOUTHWEST
THROUGH 19.08Z THEN SLOWLY SHIFTING WEST TO NORTHWEST THROUGH AT
15 TO 20 KNOTS WITH GUSTS TO 30 KNOTS THROUGH 20.00Z. 32/EE
PREV DISCUSSION... /ISSUED 422 PM CDT THU APR 18 2019/
NEAR TERM /NOW THROUGH FRIDAY/...STAY WEATHER AWARE TONIGHT.
UPPER AIR ANALYSIS SHOWS A LEAD MID TO UPPER LEVEL IMPULSE OF
ENERGY EJECTING NORTHEAST OVER THE UPPER TX COAST AND UP ACROSS
LOUISIANA. THIS HAS CREATED AN AREA OF HIGH LEVEL DIFFLUENCE
SUPPORTING A CONTINUED ENHANCEMENT OF CONVECTION AND CONCENTRATED
LIGHTNING UPSTREAM. SATELLITE IMAGERY SHOWS A MCS SPREADING
EASTWARD ACROSS THE LOWER MS DELTA TO OFF THE LA COAST. THE PRE-
STORM ENVIRONMENT WILL CONTINUE TO SHOW DESTABILIZATION THRU THE
COURSE OF THE DAY INTO THE EVENING WITH THE SLOW EASTWARD
MIGRATION OF A WELL DEFINED 1000-850 MB THETA-E MOISTURE AXIS AND
WARM SECTOR. AT SAME TIME, THE LOW LEVEL WIND PROFILES STRENGTHEN
MARKEDLY WITH 850MB SOUTH TO SOUTHWEST FLOW INCREASING TO 50 TO
60 KTS BETWEEN LATE AFTERNOON AND CONTINUING EAST TONIGHT. 0-6KM
BULK SHEAR VALUES TO INCREASE TO AS HIGH AS ~60 KNOTS FAVORING AN
INCREASED SEVERE WEATHER POTENTIAL. AN ASSESSMENT OF WET BULB ZERO
HEIGHTS ARE FAIRLY HIGH WHICH WOULD MITIGATE OCCURRENCE OF LARGE
HAIL. THUS, THE HIGHEST CONFIDENCE OF THREATS CONTINUE TO BE
CONCENTRATED ON DAMAGING STRAIGHT LINE WINDS IN EXCESS OF 70 MPH
AS HIGHER MOMENTUM AIR MIXES TO THE SURFACE IN REAR FLANK
DOWNDRAFTS WITH THE PASSAGE OF ANY BOWING CONVECTIVE LINE
SEGMENTS. THE LATEST PROBABILITIES FOR DAMAGING WINDS FROM THE
STORM PREDICTION CENTER IS A HEALTHY 45% AND FOCUSED OVER INTERIOR
SOUTHEAST MS AND INTERIOR SOUTHWEST AL TONIGHT. A 30% PROBABILITY
FOR DAMAGING WINDS IS OUTLOOKED ELSEWHERE. THERE IS ALSO A RISK
FOR TORNADOES AS THESE APPEAR TO BE MORE PROBABLE IN ANY DISCRETE
CELLS THAT FORM OUT AHEAD OF THE MAIN LINE. A FEW STRONG TORNADOES
CANNOT BE RULED OUT. NO CHANGES MADE TO DAY 1 SEVERE WEATHER
THREAT WHICH IS MAINTAINED AT ENHANCED AREA-WIDE. THE HIGH
RESOLUTION CONVECTION ALLOWING MODELS (CAM'S) STILL SHOW SOME
DIVERGENCE ON TIMING AND EVOLUTION OF CONVECTIVE MODE.
INITIALIZING CONVECTIVE TRENDS UPSTREAM WITH THE CAMS SUGGEST LEAD
AREA OF STORMS MOVING IN OVER SOUTHEAST MS BY THE CLOSE OF THE
AFTERNOON WITH SOME MOMENTARY WEAKENING. BY TONIGHT A MORE
ORGANIZED AREA OF STORMS IS PROGGED TO MOVE ACROSS WITH BETTER
DYNAMICS IN PLACE. WIDESPREAD RAINFALL AMOUNTS BETWEEN ONE TO TWO
INCHES ARE FAVORED, WITH HIGHER AMOUNTS POSSIBLE AS THE PASSAGE OF
THE STRONGEST STORMS WILL LIKELY CONTAIN HEAVY RAIN RATES CAUSING
POTENTIAL OF FLOODING IN POORLY DRAINED LOWER LYING AND URBAN
AREAS. A LIMITED FLOODING THREAT IS MAINTAINED.
WIND ADVISORY CONTINUES AREA-WIDE THROUGH LATE TONIGHT. HIGH RISK
OF DANGEROUS TO POTENTIALLY DEADLY RIP CURRENTS AND HIGH SURF
CONTINUES ALONG THE BEACHES.
FRIDAY, A FRONTAL BOUNDARY WILL BE EAST OF THE AREA WHILE AXIS OF
LARGE UPPER LOW PIVOTS EASTWARD OVER THE TN RIVER VALLEY. PLENTY
OF CLOUDS ARE FORECAST TO WRAP AROUND THIS FEATURE AND REMAIN IN
PLACE THRU THE DAY. WITH NORTHWEST FLOW AND CLOUDS, DAYTIME HIGHS
LOWER. COOLEST NUMBERS ARE EXPECTED OVER THE INTERIOR WHERE HIGHS
LOOK TO HOVER IN THE LOWER 60S. A SMALL POP CONTINUES ON FRIDAY
WITH UPPER SYSTEM CLOSE BY. /10
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...SKIES WILL
GRADUALLY CLEAR FRIDAY NIGHT AS THE UPPER LOW MOVES TO THE NORTH
AND EAST. A NORTHWEST FLOW ALOFT WILL PREVAIL THROUGH THE WEEKEND
WITH A COOLER AND DRIER AIRMASS MOVING INTO THE AREA THROUGH
SUNDAY NIGHT. /13
LONG TERM /MONDAY THROUGH THURSDAY/...TEMPERATURES WILL MODIFY
BACK INTO THE UPPER 70S AND LOW 80S MONDAY INTO TUESDAY AS UPPER
RIDGING BUILDS OVER THE AREA. MOISTURE LEVELS BEGIN TO INCREASE ON
WEDNESDAY INTO THURSDAY AS A COLD FRONT APPROACHES THE AREA. THIS
WILL BRING INCREASING CHANCES OF RAIN TO THE AREA LATE IN THE
PERIOD. /13
MARINE...MAIN IMPACTS OVER THE COASTAL WATERS IN THE NEAR TERM
WILL BE THE PASSAGE OF STRONG TO LOCALLY SEVERE STORMS TONIGHT WITH
PERHAPS A FEW TORNADOES AHEAD OF AN EASTWARD MOVING COLD FRONT.
FRONT MAKES PASSAGE LATE TONIGHT AND BRINGS A MODERATE TO STRONG
WEST TO NORTHWEST FLOW. FREQUENT WIND GUSTS TO GALE FORCE LIKELY
THRU LATE TONIGHT OVER THE OPEN GULF WATERS. A GALE WARNING IS NOW
IN PLACE FOR THIS. ELSEWHERE, SMALL CRAFT ADVISORIES LOOK TO HOLD IN
PLACE FOR SOME TIME, WITH CRITERIA NOW LOOKING TO BE MET WELL INTO
SATURDAY. MARINE CONDITIONS IMPROVE BY LATE IN THE WEEKEND INTO THE
FIRST OF NEXT WEEK AS SURFACE HIGH PRESSURE MOVES EAST OVER THE
AREA. /10
MOB WATCHES/WARNINGS/ADVISORIES
AL...WIND ADVISORY UNTIL 3 AM CDT FRIDAY FOR ALZ051>060-261>266.
HIGH RIP CURRENT RISK THROUGH LATE FRIDAY NIGHT FOR ALZ265-266.
HIGH SURF ADVISORY UNTIL 6 PM CDT FRIDAY FOR ALZ265-266.
FL...WIND ADVISORY UNTIL 3 AM CDT FRIDAY FOR FLZ201>206.
HIGH RIP CURRENT RISK THROUGH LATE FRIDAY NIGHT FOR FLZ202-204-
206.
HIGH SURF ADVISORY UNTIL 6 PM CDT FRIDAY FOR FLZ202-204-206.
MS...WIND ADVISORY UNTIL 3 AM CDT FRIDAY FOR MSZ067-075-076-078-079.
GM...SMALL CRAFT ADVISORY FROM 4 AM FRIDAY TO 11 PM CDT SATURDAY FOR
GMZ650-655-670-675.
GALE WARNING UNTIL 4 AM CDT FRIDAY FOR GMZ650-655-670-675.
SMALL CRAFT ADVISORY UNTIL 10 AM CDT SATURDAY FOR GMZ630>636.
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