Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service New Orleans la
418 am CST Wednesday Jan 28 2015

latest surface analysis showed a 1025mb over the Ohio Valley with
the associated ridge axis extending southwest to north central
Gulf and 1005mb low over the northern/Central Plains. Upper air analysis
showed the main trough axis from Maine to east of the Middle Atlantic
States. An upper level ridge axis was located from East Texas to
Minnesota and northwest flow over Mississippi Valley and eastern
one third Continental U.S..


cold air advecion was not able to offset heating of the dry air
yesterday as surf temperatures warmed above guidance levels. Today...cold
air advection will diminish as the upper ridge slide east over the
Mississippi Valley. Will go 2 to 5 degrees above guidance for
today. Not expecting an amplified ridge but heights will increase
across the lower Mississippi Valley and allow temperatures to rise to the
middle 70s on Thursday.

A strong wave in the northern stream will track across the middle
Mississippi Valley and push a front through the area late
Thursday. Will maintain cloud cover with the passage and maintain
cooler temperatures for Friday. GFS and Euro are still showing a
positively tilted broad trough over southwest Continental U.S. Over the
weekend. Southwest flow ahead of trough may yield significant
cloud cover and a chance of rain over the area over the
weekend...with the best chance of Sunday. In addition...both show
some marginal middle layer instability ahead of the trough Sunday
afternoon across northwest zones and the rest of forecast area
Sunday evening. Ergo...will insert a slight chance of thunder and
maintain likely rain chances Sunday and decreasing rain chances
Sunday night. Linger upper level low over old Mexico will finally
open and push across the central Gulf Coast Tuesday night and
Wednesday bringing a chance of rain across the south half but
keeping the warm and unstable sector south of land areas according
Euro and GFS. 18


latest observation continue to indicate no fog in sight this morning...
though not necessarily the case towards the end of the period
tomorrow morning. Clear skies and good visibilities should prevail
throughout the day. IFR to MVFR visible possible after 06z tonight at
patchy light fog develops.


nocturnal increase in offshore winds as weak backdoor front moved
through has brought winds into the 15 to 20 knot range over offshore
waters. These conditions should persist through at least middle will include exercise caution headline with this forecast
package. Surface ridge behind this front should stay north of the
area today and then rotate southeast Thursday towards Florida which
will bring local winds back around to onshore. Yet another weak
front will move through Thursday night which will bring a brief
round of exercise caution conditions. A repeat of winds rotating back
around to onshore by late Saturday is expected as progressive
pattern keeps the ridge to the north moving east. A more substantial
cold front looks to be coming in late Sunday night into Monday
morning which should bring winds up into strong Small Craft Advisory levels.


Decision support...
Activities...slurry support

Decision support services (dss) code legend
green = no weather impacts that require action
blue = long fused watch/warning/advisory in effect or high
visibility event
yellow = heightened impacts with short fused
watch/warning/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 to high risk severe
and/or direct tropical threats; events of National


Preliminary point temps/pops...
mcb 67 45 74 42 / 0 0 0 10
btr 67 47 76 45 / 0 0 0 10
asd 65 46 73 45 / 0 0 0 10
msy 65 48 74 49 / 0 0 0 10
gpt 60 48 70 48 / 0 0 0 10
pql 61 47 71 46 / 0 0 0 10


Lix watches/warnings/advisories...


National Weather Service Glossary of Abbreviations