Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA
FXUS64 KLIX 101308
Area Forecast Discussion
National Weather Service New Orleans LA
708 AM CST Sat Dec 10 2016
A stable, unusually dry, and cold atmosphere is over the region as high
pressure moves towards the Appalachians. An inversion extends from
the surface to 9000 feet and the precipitable water value is 0.33
inches, which is well below normal. The wind profile is backing,
which is indicative of the cold air advection that has been
occurring. Winds near the surface are from the northeast at the
surface and then turn counter- clockwise and blow from the west-
southwest by the upper levels. A peak wind speed of 115 knots was
at 39000 feet.
12z balloon info: A routine flight ascending for 100 minutes
reaching a height of 20.1 miles above the ground bursting near
Pascagoula 81 miles downrange from the office.
.PREV DISCUSSION... /issued 345 AM CST Sat Dec 10 2016/
Model solutions are at least in short term agreement with timing
and placement of the first two of three fronts. The first front
will move into northern Miss/La and eastern Texas before slowing
to a crawl Monday. This front will ever-so-slowly move near the
gulf coast by Tuesday evening before the second stronger front
reinforces the first and moves brings the unified front offshore.
This is where the global models end their agreement. A blend of
sensible weather will be used from the GFS and the Euro.
They both develop at least two disturbances that move along the
frontal interface Monday through Tuesday. But only the GFS wants
to produce a widespread fog scenario possibly starting as early as
Monday morning. As the first front slowly sinks south, mesoscale
advective and inversion properties look to be strong enough to
produce a widespread fog event Monday morning and Mon night but
conditions look favorable for fog to stay most if not all day
Tuesday. This will depend heavily on how strong the disturbance is
that moves through Tuesday. If the GFS is right, there will be
widespread fog with some light showers now and again Tuesday. If
the Euro is right, there will be widespread fog lifting for short
times as convective pulses moves through.
The second cold front reinforces the first Wednesday and moves out
into the gulf by Thursday. But the cloud cover and light drizzle
does not leave as the next(third) even stronger cold front is
quickly moving eastward causing return flow to develop by as
early as Thursday evening. This will cause low clouds light rain
and fog to once again develop for Friday morning and Saturday
morning. This third front`s timing, and hence placement, is where
the models stop agreeing. The GFS is a full 24hrs later with fropa
than the Euro. Since this front actually sits outside the current
forecast`s domain, it will allow for a few more model runs before
trying to find a credible solution.
VFR conditions will prevail through the TAF period. 13/MH
Winds will continue to decrease throughout the day. Small Craft
should exercise caution through this evening as winds will still be
in the 15 to 20 knot range for a portion of the day. Winds will
finally die down later on this afternoon and evening. As high
pressure moves east, winds should remain below headline criteria
into the middle of next week, until the next cold frontal passage
Wednesday night or Thursday. 13/35
DSS code: Blue.
Decision Support Services (DSS) Code Legend
Green = No weather impacts that require action.
Blue = Long-fused watch, warning, or advisory in effect or
high visibility event.
Yellow = Heightened impacts with short-fused watch, warning or
advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
tropical events; HazMat or other large episodes.
Red = Full engagement for Moderate risk of severe and/or
direct tropical threats; Events of National Significance.
.PRELIMINARY POINT TEMPS/POPS...
MCB 53 35 67 58 / 0 0 0 30
BTR 55 39 69 61 / 0 0 10 30
ASD 55 36 68 58 / 0 0 10 20
MSY 55 46 70 61 / 0 0 10 20
GPT 56 39 67 60 / 0 0 10 20
PQL 56 35 67 58 / 0 0 10 20
LA...Freeze Warning until 8 AM CST this morning for LAZ034-040-
MS...Freeze Warning until 8 AM CST this morning for MSZ080>082.