Area Forecast Discussion
Issued by NWS Jackson, MS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
065
FXUS64 KJAN 251509 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
909 AM CST Sat Feb 25 2017

.UPDATE...
Updated for morning discussion.

&&

.DISCUSSION...
Looks to be a nice day today with temperatures closer to average.
Did a minor tweak to temps and dewpoints a in the past hour but
now thinking I may need to boost temperatures up further (at least
along and southeast of the Natchez Trace corridor) as cold air
aloft is lagging quite a bit behind the switch to northwest winds.
Also, expect very dry air this afternoon to present at least a
minor fire weather concern. Will include a section on this threat
below. /BB/

Prior discussion below:

Today through tonight...

Cold, dry air continues to advect into the region from the
northwest this morning after last night`s frontal passage.
Temperatures have already fallen into the mid 40`s in the Delta.
Temperatures should fall another 5-10 degrees before sunrise
throughout the region.

Upper level flow will be mostly zonal today as high pressure
filters in at the surface from the west. The surface high will
become centered over the Mid-South by 00Z. Temperatures will
struggle to reach normal values this afternoon, a rarity this
February. Drier air and moderate winds throughout the day will
result in a fire weather concern worth noting but due to high fuel
moisture content and cool temperatures, it will be omitted from
the HWO. An increased radiational cooling effect will be present
in the northern portions of the ArkLaMiss overnight, closer to the
center of the surface high. This will result in some locations
north of the I-20 corridor falling slightly below freezing early
tomorrow morning.

Sunday through next week...

The surface high that will be over the region through the weekend
will begin to track eastward late Saturday and continue to move east
on Sunday. This will put the region on the western periphery of this
surface high, and thus southerly flow will return. The upper pattern
will initially be zonal on Sunday morning and quickly transition to
more of a southwest flow by Sunday afternoon. Overall, Sunday will
remain dry with highs some 10 degrees warmer than Saturday. Readings
will return to the 60s(lower 60s in the north and upper 60s in the
south) and even some lower 70s. Moisture will slowly return through
the day, but overall atmospheric moisture will remain low with
dewpoints in the 40s at best and PW values not quite an inch in the
west/southwest by evening.

Moisture will return a little quicker come Sunday evening as a
disturbance moves through the southwest flow aloft. This will bring
the first round of showers to the region overnight Sunday night into
early Monday morning. As instability gets a little better during the
day Monday, there will be a better chance to see some thunderstorms.
Mid-level lapse rates will be around 6.5-7C/km. vertical totals
around 27-29C and some MUCape around 1500-1800 J/kg in the south
looks possible, shear will be a little more marginal but it won`t be
out of the question to potentially see a strong to perhaps isolated
severe storm. However, the upper jet will weaken during the day and
heights will also increase which could hamper any more robust
convection. This will be something to monitor through later
forecasts.

This impulse will move off late Monday and as this does but enough
rain/storms may linger across northern areas Monday night. A surface
low will develop across the south central Plains states and track
northeast on Tuesday, this will help drag a front toward the Ozarks.
As this occurs, coupled with daytime heating, additional showers and
storms look to develop in the warm sector, which includes the
northern part of the ArkLaMiss region. Further south, some capping
may limit more coverage of convection further south.  Another
surface low looks to develop in its wake/along the front in central
Oklahoma during the afternoon Tuesday. As this tracks to the
northeast later Tuesday night and especially during the day on
Wednesday, it will drag a cold front toward and through the
ArkLaMiss region. A mid-level trough will swing behind this feature
Wednesday evening into Wednesday night. Showers and thunderstorms
will occur along the front as it moves through the ArkLaMiss. Given
the warm, moist airmass in place along with enough shear, continued
steep lapse rates and forcing from this upper level system,
scattered showers and thunderstorms will be possible including some
severe storms. A mention of this may be included this morning in the
HWO/graphics.

The front will move through the region late Wednesday night, thus
ending the chances for rain and storms. High pressure will once
again move into the region for the weekend. As far as temperatures,
continued above normal highs will occur through the week ahead of
the front with readings in the 70s and again some 80s are possible
on Tuesday. Overnight lows will be in the 60s. Once the front
passes, a return to more seasonable temperatures will occur with
highs in the 60s and overnight lows in the 30s and 40s. /28/

&&

.AVIATION...
12Z TAF discussion:
VFR conditions will prevail today. Gusty winds from the north will
subside after sunset. /jpm3/

&&

.FIRE WEATHER...
Sustained northwest winds to 8 to 14 mph this afternoon (with
occasional gusts near 20 mph) will combine with afternoon RH
values in the 20 to 30 percent range to bring a limited fire
danger risk. One thing that should keep the risk from getting out
of hand is the fact that fuel moisture is not terribly low. Will
include risk in the HWO and graphics. /BB/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       58  34  66  51 /   4   0   0  36
Meridian      61  32  65  46 /   8   0   0  21
Vicksburg     58  33  68  53 /   1   0   1  45
Hattiesburg   65  35  68  50 /   7   0   0  11
Natchez       59  36  68  56 /   2   0   0  39
Greenville    52  32  62  49 /   1   0   1  56
Greenwood     54  31  64  50 /   2   0   0  52

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.

&&

$$

JPM3/28/BB



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.