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Area forecast discussion 
National Weather Service Fort Worth Texas
702 am CDT sun may 3 2015

Aviation...

For the 12z tafs...VFR conditions and southerly winds are
expected through early tomorrow morning with MVFR ceilings moving in
before sunrise Monday.

Early morning infrared satellite imagery showed low-level stratus
developing over The Hill Country southwest of area taf sites. The
low-level clouds are expected to remain west or southwest of area
taf sites today. VFR clouds are likely today with just cirrus to
start off the day...joined by some scattered cumulus clouds this
afternoon. These clouds are expected to be based around 6 to 7 kft
above ground level. Persistent southerly winds are expected to bring some deeper
Gulf moisture into the region by early tomorrow morning. This
deeper moisture should result in MVFR stratus building north over
area taf sites before sunrise on Monday. MVFR ceilings will likely
lift or scatter out to VFR conditions by noon on Monday.

Cavanaugh

&&



Previous discussion... /issued 336 am CDT sun may 3 2015/

Upper level ridging will prevail across the region today and
tonight and then we begin a transition to southwest flow aloft as
an upper level trough moves into the southwest Continental U.S. On Monday.
Temperatures today will be slightly warmer than yesterday with
most of the region reaching the lower 80s this afternoon. South
winds will increase to 10 to 15 miles per hour and there will be some clouds
around. Overnight lows tonight will be warmer with most of the
region in the lower 60s. Overnight lows will continue to steadily
warm over the next several days as moisture values and dewpoints
rise. Monday will be another quiet and pleasant day with some
added cloud cover but afternoon highs still in the upper 70s to
lower 80s.

The upper level trough that moves into the southwestern Continental U.S. On
Monday will move northeast into Colorado...New Mexico and the
Texas Panhandle Tuesday afternoon. This trough will provide
large scale lift for showers and thunderstorms in north and
central Texas...mainly Tuesday afternoon through Wednesday
morning. The track of this upper level trough keeps the best lift
west of the area but continue to advertise 60-70 probability of precipitation over our
western counties...tapering to 30-40 percent in our eastern
counties. Instability parameters continue to support the potential
for a few strong or marginally severe storms but widespread severe
weather is not expected. South winds today and tomorrow will
continue bringing moisture-rich air into the area and precipitable water values
will increase to about 1.5-2 inches. These values are well above
normal for this time of year suggesting heavy rain and localized
flooding will be a threat. Highest quantitative precipitation forecast totals are expected to be
west of Interstate 35/35w in areas where lake levels are still low
and drought conditions are worse. Hopefully these areas can see
some beneficial rainfall Tuesday and Wednesday.

The upper level trough continues a north-northeastward trajectory
into the plains on Wednesday leaving southwest flow aloft in its
wake over North Texas. We continue in this pattern aloft through
at least next weekend as another upper level trough moves into the
western Continental U.S. And then ejects eastward across the northern
plains...well north of Texas. In the Wednesday to Friday
time frame...diffluence aloft is fairly prominent and may
continue into the weekend. Under this pattern of divergence aloft
dominated by southwest flow...rain chances will continue across
the region through the end of the week.

The region will not be affected by another strong upper level
trough or disturbance beyond Wednesday...but the diffluence aloft
combined with a weakly capped and moisture-rich environment may
be enough for isolated to scattered showers and thunderstorms each
afternoon and evening. Also...a weak disturbance in the southwest
flow aloft could be enough to provide lift for convection...and
the GFS and European model (ecmwf) both show a potential disturbance moving
through on Thursday. Have kept probability of precipitation in the 30-40 percent range
Wednesday through Saturday anticipating mostly diurnally driven
showers/thunderstorms will be possible each afternoon and evening.
The dryline may also be a focus for storm initiation each day but
it is forecast to remain in West Texas through the week. Any
storms moving off the dryline may dissipate before reaching our
County Warning Area.

Isolated strong or marginally severe storms are possible Wednesday
through Friday. Instability parameters are not very impressive but
cape values are between 500-1500 j/kg with a weak cap.
However...shear values are on the lower end and lapse rates are
weak as well. Heavy rainfall will continue to be a threat due to
precipitable water values remaining well above normal. By the weekend...GFS
forecast soundings suggest the cap will strengthen and it may be
tough to get convection by then.

Jldunn

&&




Preliminary point temps/pops...
Dallas-ft. Worth, Texas 82 63 82 63 79 / 0 5 10 10 50
Waco, Texas 82 62 82 63 81 / 5 10 10 10 50
Paris, Texas 81 59 81 61 80 / 0 5 5 10 40
Denton, Texas 82 62 81 62 78 / 0 5 10 10 50
McKinney, Texas 82 61 81 61 79 / 0 5 5 10 50
Dallas, Texas 84 63 84 64 79 / 0 5 5 10 50
Terrell, Texas 83 61 84 63 79 / 0 5 5 10 50
Corsicana, Texas 81 61 83 63 79 / 5 5 10 10 50
Temple, Texas 82 62 83 63 79 / 5 10 10 10 50
Mineral Wells, Texas 83 61 81 61 78 / 5 10 10 10 60

&&

Forward watches/warnings/advisories...
none.

&&

$$

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