Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 020904
AFDHUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
404 AM CDT THU JUL 2 2015

.DISCUSSION...
ACROSS THE GREATER NORTH AMERICAN DOMAIN...A CONFIGURATION OF STRONG
RIDGING OVER THE DESERT SW AND TROUGHING NEAR THE ATLANTIC SEABOARD...
HAS PLACED THE FORECAST AREA IN A POTENTIALLY STORMY NORTHWESTERLY
FLOW. THIS SETUP WAS SENDING WAVES OF UPPER LEVEL DISTURBANCES
ACROSS THE REGION. THOSE DISTURBANCES INTERACTING WITH A MOIST AND
UNSTABLE ENVIRONMENT...WERE CAUSING SCATTERED TO NUMEROUS SHOWERS
AND STORMS. AN UPPER DISTURBANCE/MESOSCALE CONVECTIVE TYPE COMPLEX
THAT BROUGHT PRECIP ACROSS THE AREA ON WED HAS SIGNIFICANTLY
WEAKENED AS REMNANTS OF IT MOVE THROUGH THE TROUGH AXIS ALONG THE SE
COAST. ANOTHER COMPLEX NOW AFFECTING AREAS FROM SW MISSOURI TO THE
TN/OH/MS RIVER JUNCTURE WAS HEADED SE IN THE PREVAILING FLOW. THE
FORECAST FOR TODAY/TONIGHT HINGES ON HOW MUCH OF IT REMAINS AS IT
MOVES ACROSS THE CENTRAL TENNESSEE VALLEY. ANOTHER UPPER SYSTEM
MOVING OVER THE WESTERN HIGH PLAINS...SOUTH OF THE BLACK HILLS COULD
BECOME A PLAYER IN OUR SENSIBLE WEATHER ON FRI/SAT.

AT THE SURFACE...A STATIONARY FRONT WAS POSITIONED WEST TO EAST FROM
THE NEBRASKA PANHANDLE TO THE MID ATLANTIC. A WEAK LOW MOVING ALONG
THIS BOUNDARY SHOULD RESULT IN THE FRONT MOVING SOUTHWARD SOMEWHAT...
A LITTLE CLOSER TO THE FORECAST AREA. THE 00/06Z NAM WERE THE MOST
AGGRESSIVE BRINGING IT TOWARD THIS AREA...WHILE THE OTHER MODELS
KEPT IT FURTHER TO THE NORTH. IN EITHER CASE...THE BETTER PROGGED
UPPER LEVEL SYSTEMS NEARING FROM THE NW WILL KEEP VERY GOOD CHANCES
OF RAIN CONTINUING INTO THE WEEKEND.

GIVEN THE FORECAST AREA SHOULD REMAIN IN A GENERAL TROUGHING PATTERN
AND NW FLOW ALOFT...WILL KEEP HIGH PRECIP CHANCES GOING. INCREASED
THIS MORNING`S RAIN CHANCES TO LIKELY...THEN CATEGORICAL FOR THE
AFTERNOON AND EVENING. THIS SHOULD COINCIDE WITH THE CONVECTION OVER
SW MISSOURI NEARING THE AREA LATER TODAY. AS WAS THE CASE ON WED...
STRONG TO SEVERE STORMS ARE AGAIN POSSIBLE...ESPECIALLY IF MORE
DAYTIME HEATING PRODUCED INSTABILITY OCCURS. THE NAM WAS SHOWING MORE
SHEAR AS THE DAY PROGRESSED...PROBABLY BECAUSE OF INCREASED HELICITY
FROM THE APPROACH OF THE MAIN SURFACE BOUNDARY. MAIN THREATS FROM ANY
SEVERE STORMS THAT FORM WOULD BE STRONG TO DAMAGING WIND GUSTS AND
MARGINALLY SEVERE HAIL.

PRECIP WATER AMOUNTS RANGING FROM 1.7 TO 2.1 INCHES INTO SATURDAY...
WILL BRING A POTENTIAL OF LOCALLY HEAVY RAINS. A FLOODING RISK
CONTINUES...ESPECIALLY IF CELLS TRAIN OVER THE SAME AREA. MODEL RUN
RAINFALL TOTALS THROUGH SAT INDICATE 1-3 INCHES ACROSS THIS AREA...
WITH HIGHER AMOUNTS TO OUR NORTH. THE GFS THIS GO AROUND WAS THE
DRIER RUN...WITH THE NAM/ECMWF THE WETTER (AGAIN MAINLY NEAR AND
NORTH OF THE TN/AL BORDER). GIVEN THAT MOST OF THE AREA HAS REMAINED
ON THE DRY SIDE OVER THE LAST MONTH OR SO...AND THE HEAVIEST RAINS
SHOULD REMAIN TO OUR NORTH...WILL HOLD OFF ON A FLASH FLOOD WATCH
THIS AM.

THE TROUGHING PATTERN SHOULD RELAX SOMEWHAT DURING THE COURSE OF
EARLY NEXT WEEK. AN UPPER LEVEL SYSTEM NOW IMPACTING THE GULF OF
ALASKA WILL MOVE EASTWARD AND AMPLIFY AS IT MOVES OVER THE SOUTH/
CENTRAL CANADIAN PROVINCES...RESULTING IN THE EAST COAST TROUGHING
RELAXING SOMEWHAT. AN UPPER LOW IS ALSO FORECAST TO FORM OFF OF THE
BAJA AND CALIFORNIA COAST...WEAKENING THE DESERT SW UPPER RIDGE. THE
GFS/ECMWF BOTH SHOW UPPER RIDGING TRYING TO BECOME ESTABLISHED OVER
THE GULF REGION. THE OUTPUT THIS FAR OUT IS STILL UNCERTAIN...BUT A
DRIER TREND COULD BE IN THE OFFING AFTER THE MIDDLE OF NEXT WEEK.

RSB

&&

.AVIATION...
/ISSUED 1159 PM CDT WED JUL 1 2015/
FOR 06Z TAFS...MVFR VISIBILITIES ARE EXPECTED AT HSV DURING THE
INITIAL PORTION OF THE FORECAST DUE TO FOG...WHILE MSL SHOULD REMAIN
VFR. BY BETWEEN 09Z-12Z...MVFR CEILINGS AND VISIBILITIES ARE
EXPECTED AT BOTH HSV AND MSL. EXPECT THE LOWER CEILINGS AND
VISIBILITIES DUE TO SHRA/TSRA TO CONTINUE AT BOTH TERMINALS UNTIL
AROUND 16Z. EXPECT BORDERLINE MVFR TO VFR CEILINGS AT BOTH HSV AND
MSL THROUGH THE REST OF THE FORECAST PERIOD WITH AT LEAST VCTS.

TT

&&

.PRELIMINARY POINT TEMPS/POPS...
HUNTSVILLE    85  70  85  69 /  80  80  60  50
SHOALS        85  70  84  70 /  80  80  60  50
VINEMONT      84  69  84  69 /  80  80  60  50
FAYETTEVILLE  83  69  83  68 /  80  80  60  50
ALBERTVILLE   83  69  82  69 /  80  80  60  50
FORT PAYNE    83  68  83  68 /  80  80  60  50

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.


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