000
FXUS64 KBMX 151741
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1240 PM CDT SAT JUN 15 2013

.UPDATE...
AVIATION DISCUSSION.

&&

.DISCUSSION...

A SURFACE HIGH WAS CENTERED OVER THE MIDDLE ATLANTIC STATES WITH A
RIDGE AXIS EXTENDING INTO THE SOUTHEAST STATES. AN INVERTED
SURFACE TROF FROM MOBILE TO ATLANTA WAS CREATING A TIGHTER
PRESSURE GRADIENT OVER SOUTHEAST ALABAMA AND SOUTHEAST SURFACE
WINDS HAVE BEEN GUSTING TO 20 MPH. WITH SOUTHEAST WINDS RETURNING
TO THE AREA...HUMIDITIES ARE ON THE RISE WITH SURFACE DEWPOINT
TEMPERATURES BACK INTO THE MIDDLE TO UPPER 60S. THE AIR MASS IS
STILL TOO DRY ALOFT TO SUPPORT ANY DIURNAL CONVECTION TODAY. NO
SIGNIFICANT CHANGES MADE TO FORECAST.

58/ROSE

&&

.AVIATION...
18Z TAF DISCUSSION.

MAINLY VFR CONDITIONS EXPECTED THRU THE PERIOD. FAIR WEATHER SCT
CUMULUS WITH BASES ARND 5000 FEET AGL WILL DISSIPATE SHORTLY AFTER
SUNSET. MODELS ARE BRINGING IN A SURGE OF LOW LEVEL MOISTURE FROM
THE SOUTHEAST ARND 10Z.  CONFIDENCE IS HIGH FOR THE FORMATION OF
CLOUD COVER...BUT LOW CONFIDENCE IN CIG HEIGHT. ADDED MVFR CIGS AT
KMGM AND KTOI.  LOW CLOUDS WILL PROBABLY REACH NORTHERN TAF SITES BY
15Z...BUT CIGS MAY BE MORE RELATED TO CUMULUS FORMING DURING MORNING
HEATING AND CIGS SHOULD BE HIGHER.


58/ROSE


&&

.PREV DISCUSSION...
/ISSUED 620 AM CDT SAT JUN 15 2013/

AN UPPER RIDGE AND NORTHWEST FLOW ALOFT START OFF THE PERIOD BUT
THE SYNOPTIC PATTERN FLATTENS OUT SIGNIFICANTLY THROUGH MONDAY.
THIS ALLOWS SEVERAL RIPPLES IN THE WESTERLY FLOW TO PENETRATE
SOUTHWARD. MOISTURE WILL INCREASE AND A COLD FRONT WILL APPROACH
THE AREA BY MONDAY AND TUESDAY. THIS PERIOD APPEARS TO BE THE MOST
UNSETTLED DURING THE FORECAST TIME FRAME AND WILL CONTINUE THIS
ADVERTISED TREND. THE VARIOUS MODEL SOLUTIONS ARE IN RELATIVELY
GOOD AGREEMENT THROUGH TUESDAY AND THEN SOME DIFFERENCES START
SHOWING UP. THE GFS APPEARS TO BE THE OUTLIER IN MOVING A SLIGHTLY
DEEPER TROUGH EASTWARD FASTER AND THEREFORE ALLOWING A COLD FRONT
TO PUSH THROUGH ALL OF CENTRAL ALABAMA. THE OTHER MODELS ARE NOT
NEARLY AS AMBITIOUS...INCLUDING THE ENSEMBLES. THE CONSENSUS KEEPS
THE STALLED BOUNDARY ACROSS CENTRAL ALABAMA IN A WEAKENED STATE.
BY SATURDAY...THE MODELS ARE COMPLETELY OUT OF PHASE.

WARM AND SOMEWHAT DRY CONDITIONS ON TAP FOR YOUR SATURDAY. MEAN
MOISTURE VALUES INCREASE ENOUGH TO MENTION POPS ON SUNDAY AND
SUNDAY NIGHT. UPWARD MOTION AND FORCING INCREASE AS THE MAIN UPPER
TROUGH AND COLD FRONT APPROACH MONDAY AND TUESDAY. WILL KEEP POPS
FAIRLY HIGH THIS ENTIRE PERIOD. SLIGHTLY LOWER POPS WEDNESDAY AND
MORE FOCUSED NEAR THE WEAKENING FRONT SOUTH. THEREAFTER...WILL
SWITCH TO A MORE DIURNALLY ENHANCED RAIN CHANCE. IF THE LEFTOVER
BOUNDARY ACTS AS MORE OF A FOCUS THAN ANTICIPATED...POPS MAY BE A
BIT HIGHER THURSDAY AND FRIDAY. CONFIDENCE WAINS BY SATURDAY AND
SUNDAY AS THE MODELS GO OUT OF PHASE AND WILL KEEP NEAR
CLIMATOLOGICAL POPS.

MODERATE INSTABILITY WILL DEVELOP BOTH MONDAY AND TUESDAY. BULK
SHEAR VALUES ARE NOT IMPRESSIVE AND UPPER LEVEL TEMPERATURES ARE
RATHER WARM. BUT THERE WILL BE AN UPPER LEVEL DISTURBANCE AND
A COLD FRONT TO AIDE IN LIFT AND FORCING. ALSO...SB CAPE VALUES
FORECAST IN THE 2000-2500 RANGE WITH DOWNDRAFT CAPE 800-1000 AT
TIMES. AT THIS TIME...BELIEVE A FEW STRONG STORMS WILL BE
POSSIBLE MONDAY AND TUESDAY WITH SOME GUSTY WINDS AND BRIEF HEAVY
RAIN.

75

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     87  65  88  69  86 /   0   0  20  20  70
ANNISTON    88  67  88  71  86 /   0   0  20  20  60
BIRMINGHAM  90  71  90  74  88 /   0   0  20  20  70
TUSCALOOSA  92  72  92  73  90 /   0   0  20  20  70
CALERA      89  69  90  73  87 /   0   0  20  20  60
AUBURN      87  68  87  72  87 /   0   0  20  20  50
MONTGOMERY  93  71  93  73  91 /   0   0  20  20  40
TROY        92  70  92  72  91 /   0   0  20  20  30

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$