Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Brownsville Texas
534 am CST Thursday Nov 27 2014
Discussion...updated for latest aviation discussion below.
Aviation...visibility at Brownsville and Harlingen has been
problematic the last few hours as shallow ground fog has developed
due to strong radiational cooling and light winds overnight. The
fog should dissipate as the sun rises. In addition...a weak cold
front is evident moving south across northern portions of the area
and should bring light north winds and drier air in the next few
hours...further working against lingering fog. Other than morning
fog...however...conditions will be VFR today under mostly sunny
skies and light north to northeast winds.
Previous discussion... /issued 328 am CST Thursday Nov 27 2014/
Short term /today through Friday/...shallow ground fog has set up
near the coast of southeast Cameron County this morning...but should
burn off quickly with sun up. Middle level ridging upstream to the
northwest will remain strong...shifting slowly east and flattening
somewhat in the short term. A weakness aloft over north central
Mexico will stay to the west for now. Otherwise...high pressure
descending south from the plains will arrive in the area today...
bringing a light northeast to east winds but without much other
effect. Conditions will remain dry and clear with high temperatures near
normal in the middle 70s. By tonight high pressure over the northwest
Gulf will be shifting east with winds veering to southeast by Friday.
Low temperatures tonight will be a bit warmer in the lower to middle 50s but
actually pretty close to normal. Skies will be mostly clear. The
combination of high pressure in the Gulf and pressure falls in the
central and northern plains will set up light southeast to south
winds on Friday under mostly sunny to partly cloudy skies from a few
low clouds...though it will still be pretty dry with precipitable water well below
an inch. High temperatures will again be in the middle 70s.
Long term /Friday night through Thursday/...
Lee troughing over the Central Plains and ridging over the
northeastern and central Gulf of Mexico will lead to a breezy
Saturday afternoon. Temperatures will run to around 80 degrees with dry air
just above the boundary layer mixing down and reducing afternoon
dewpoints which should result in a very pleasant day. Similar
conditions are expected for Sunday and Monday but wind speeds will
decrease a few miles per hour from one day to the next through that time.
00z GFS/European model (ecmwf) and 00z GFS ensembles are in pretty good agreement sending a
front into south Texas on Monday afternoon. The airmass change is
driven by a modest increase in low level ridging over the plains and
will be fighting against east to southeasterly winds in the
850/925mb layer. This results in the front washing out/stalling near
the area. First...moisture will be very limited above about 900mb so
significant precipitation/showers appear unlikely. Did continue 20 percent probability of precipitation
for showers mainly east of Highway 281 during the day on Tuesday.
Otherwise the forecast remains pretty dry save the typical sprinkles
showers early in the morning over the Gulf and along the coast. Kept
a slight cooldown in the forecast Tuesday with cooler air behind the
front working in...at least briefly.
Southeasterly winds look to work back into place by Wednesday with
conditions returning about where they were earlier in the week.
Highs will be about 77 to 81 with some humidity/low level moisture
but nothing particularly oppressive. Rain chances appear very low.
Both the operational GFS/European model (ecmwf) have slowed/modified the synoptic
picture Thursday into Friday to keep the prospects of
another...stronger front at Bay for now. /68-jgg/
today through Friday...light south winds will become light northeast
today as plains high pressure makes its way south into the northwest
Gulf of Mexico. The high pressure will shift rapidly east however...
and by Friday light winds will again be out of the southeast. Wave
heights will remain low to moderate through 36 hours.
Friday night through Tuesday...
southeast winds will increase through Saturday and Saturday night.
At lease exercise caution conditions are forecast with Small Craft
Advisory level winds and seas possible Saturday night. Wind speeds
are forecast to become more moderate on Sunday and Monday with the
lightest winds forecast on Tuesday as a weak front approaches from
central Texas. Seas are forecast to remain low to moderate during
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