Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New Orleans la
435 am CDT Friday may 22 2015
surface map revealed a stalled frontal boundary from South
Carolina coast to Big Bend Florida to southeast Louisiana coastal
waters to south Texas. In addition...a 1023mb high was located of
the middle south and about a 4mb change from the McComb to MS Delta.
North winds of 5 to 12 knots were common across the forecast area
this morning. More so...dewpoint readings range from the upper
50s over southwest MS to near 70 near MS Delta. Precipitable
water value plots showed a moisture axis along Texas and Louisiana
coast with values of 1.6 to 1.75 inches. Upper air charts showed a
low over south cali...a high over Mexico...diffluent flow over
West Texas and weak west flow over lower Mississippi Valley. 18
moisture axis will pool along the coast...west of the Mississippi
Delta to south central Louisiana this morning through this
afternoon. Middle layer instability is present with this layer. As a
result...showers and thunderstorms are expected to form in this
general area. Dry air and less moisture with precipitable water values 1.4 to 1.5
inches over MS coast and north of tidal lakes will hamper
thunderstorm development today. Cold air advection will lower
1000-700mb from 3025m to 2990m across north zones and 3020m today.
This feature along with cloud cover will hamper high sun angle a
little bit to lower highs about 4 to 6 degrees today. Lower
dewpoints and lower thickness will allow evening and night time
temperatures about 6 to 10 degrees for some locations. The associated
surface high will move to the East Coast by midday Saturday and
yield a southeast flow over the plains and west part of the lower
Mississippi Valley. Hence...west zones will see increase in rain
chances on Saturday but dry for MS coast on Saturday.
Sunday and the rest of the forecast period will have a good
chance of rain in the forecast. The main low will track west
across The Rockies Sunday and over the plains Monday. Moisture
will pool ahead of the trough axis over the Southern Plains. The
close proximity and open Gulf will yield likely rain chances each
afternoon Monday through Wednesday across the north and west
zones. Trough will remain over the plains but not as sharp latter
part of next weak. Moisture will remain across the area.
Therefore...rain chances will decrease but not much for Thursday
and Friday of next week. 18
ceilings should remain at or above 003 for all sites. Will only show
small restrictions due to visible this morning. Should see most sites
free of any thunderstorms in the vicinity today with the exception of hum and possibly btr.
Will only show for hum today as dry air will be very close to btr.
If something develops around btr it will be to the west. Ceilings
should stay in the 020 area with some groups of 005 moving through
Marine...cold front will move into the coastal waters this morning
and stall. As the front erodes...winds will begin to freshen to
around 15 then 15-20kt by Sat night or sun ahead of the next system
developing in the Oklahoma/Nebraska area. This system will not make
much progress eastward but it will be able to kick out a few
prefrontal troughs that will carry sh/ts into the northern Gulf by
Tuesday. Moderate winds out of the southeast will remain through Wednesday before
easing back to a more manageable 10kt by the end of the week.
Activities...monitoring rivers along Mississippi coast for flooding.
Decision support services (dss) code legend
green = no weather impacts that require action
blue = long fused watch/warning/advisory in effect or high
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 risk severe and/or direct
tropical threats; events of National significance
Preliminary point temps/pops...
mcb 81 64 86 70 / 20 10 30 20
btr 83 69 86 72 / 30 20 40 20
asd 82 67 86 72 / 30 10 20 20
msy 82 73 86 75 / 40 20 30 20
gpt 82 69 85 75 / 20 10 20 20
pql 82 63 86 72 / 20 10 10 20