Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/19/18
Area Forecast Discussion
National Weather Service Denver/Boulder CO
822 PM MDT Sun Mar 18 2018
UPDATE Issued at 708 PM MDT Sun Mar 18 2018
Issued a Winter Weather Advisory for the Denver area, southern
foothills, eastern Adams, and eastern Arapahoe, and Washington
counties. With the earlier change over to snow expect snowfall
amounts of 2-5 inches in the Denver area. Roads are being slushy
in places, mainly at slightly higher elevations. As temperatures
falls and with the loss of sunshine, most roads should become
slushy or snow covered and be slippery this evening.
UPDATE Issued at 620 PM MDT Sun Mar 18 2018
Strong spring storm will race across the region tonight.
Precipitation west of I-25 has changed to snow or will shortly in
the few locations it hasn`t. Nudged snowfall amounts up a little to
reflect the earlier change over the snow. This puts snowfall amounts
in the 2-4 inch range for the Denver area. HRRR and RAP models show
the precipitation ending in the metro area around or a little before
midnight. If the heavy precipitation rates linger for a few hours or
if it appears snow will last a little longer may need to expand the
winter weather advisories.
&&
.SHORT TERM...(This evening through Monday)
Issued at 258 PM MDT Sun Mar 18 2018
Satellite pictures are showing an oblong circulation right over
the four corners at the bottom of the upper trough to our west.
Convection is breaking out over the high mountains and foothills
and Palmer Ridge at this time. There is a bit of lightning
detected over southwestern Larimer County. The cloud shield of the
system is slow to get across the CWA. Have been backing
off/delaying the cloudiness on the GFE grids all day. The wind
field over the plains shows mainly northeasterlies in place at
this time. The 12Z models all show an upper closed low over the
northeastern corner of the Texas Panhandle at 06Z and over
southeastern Kansas at 12Z. I suppose it better get moving.
Weakening zonal flow aloft is progged all day Monday. The
strongest QG ascent is progged at 00Z late this afternoon. The
system is moving quickly and by 06Z-09Z tonight downward energy
is in place over the CWA; pretty strong too. The low level winds
are progged to be north-northeasterly into mid evening, then more
north-northwesterly for the rest of tonight. They are due
northerly all day Monday. Moisture-wise, there should be plenty
over the CWA tonight, and fairly deep as well. Models have quite
a bit still around on Monday too. The QPF fields have measurable
precipitation across all of the the CWA tonight. There is some in
the high mountains all day Monday. Overall, the 12Z model runs
showed a bit less precipitation than the previous runs. Will keep
the current highlights going as is. Strong wind gusts will cause
havoc to travelers later tonight with blowing snow. Areas under
decent convection could see more precipitation and snow then is
expected otherwise. Monday`s highs will be about 10-15 F below
normals for the plains and foothills.
.LONG TERM...(Monday night through Sunday)
Issued at 238 PM MDT Sun Mar 18 2018
By Monday night, the upper level trough will push eastward bringing
NW flow over the state. Conditions on the plains will be dry, but
some light snow will continue in the mountains with model cross
sections showing decent mid level moisture through the morning
hours. Less than an inch in accumulations will be possible.
Tuesday and Wednesday will see upper level ridging increasing
bringing a period of dry conditions and warming temperatures.
Temperatures should rebound back to above normal conditions with
highs in the 60s.
The next weather system will be moving onshore over the western
coast by Thursday with continued ridging over the state. WAA will
increase 700mb temps in the +6-7C range. This will give surface
temperatures on the plains of lower 70s, the warmest day of the
week. In the mountains, increased subtropical moisture from the SW
ahead of the trough will bring increased chances of light rain and
snow to the western slopes through the day Thursday. Thursday night
into Friday and upper level shortwave combined with some CAA from
the WNW will help to bring cooler temperatures and accumulating snow
to the mountains Thursday night into Friday. A deep surface low over
the CO/KS border will help to maintain dry conditions on the plains
through Friday morning according to the GFS. The EC is slightly
slower with the progression of the upper level energy that could
bring a slight chance of rain to the plains by Friday afternoon.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 815 PM MDT Sun Mar 18 2018
IFR and LIFR cigs and vsbys due to snow and fog exist at all
Denver area air terminals as of 02z/Monday. These conditions are
expected to improve first across northwest portions of the metro
area such as at KBJC within the next few hours, then at KDEN by
around 07z/tonight, followed by KAPA an hour or two after that.
Roads and runways could become snow and/or slush covered with
slowly falling temperatures, if they haven`t done so yet. However,
road surfaces remain rather warm, so serious ice accumulation is
not anticipated. Should see MVFR conditions at all airports by 10z
tonight and VFR conditions on or before 12z/Monday with this
latest storm system racing off to the east. Winds are forecast to
remain northerly overnight at sustained speeds of 10-22kts, with
higher gusts in the 20-30kt range prior to 07z tonight.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM MDT Monday for COZ035-036-
039>041-045-046-049.
Winter Weather Advisory until noon MDT Monday for COZ031-033-034.
&&
$$
UPDATE...Baker
SHORT TERM...RJK
LONG TERM...Bowen
AVIATION...Baker
Area Forecast Discussion
National Weather Service Fort Worth TX
906 PM CDT Sun Mar 18 2018
.UPDATE...
The storms that moved through North and Central Texas early this
evening have either dissipated or moved to the east. The
remainder of the evening will be quiet overall. However, we will
see an increase in winds as a cold front translates from west to
east across the region. A few showers and storms may accompany the
cold front overnight, mainly across the east/northeast zones
where moisture and instability will be the most abundant. Severe
storms are not expected with the overnight activity.
Have sent an update to the forecast to remove Severe Thunderstorm
Watch 11 from all counties and remove PoPs from all but the
eastern zones. No other major changes were made.
79
&&
.AVIATION... /Issued 659 PM CDT Sun Mar 18 2018/
/00z TAFs/
With scattered convection moving quickly east of the I-35
corridor, VFR conditions will prevail across North Central Texas -
with wind becoming the primary impact Monday.
A strong mid-level shortwave trough exiting the southern Rockies
this evening will zip eastward into Mississippi Valley by Monday
afternoon. This will create a strong, deep westerly flow regime
across the region by mid-morning Monday. Westerly surface winds
should increase to 20 knots sustained at the DFW-area TAF sites,
gusting at times in excess of 30 knots from 16z through 00z. These
winds will veer gradually to a NWly direction through the afternoon,
creating some potential crosswind issues at KDFW for several
hours. The gradient will be slightly weaker across Central Texas,
and have backed off the wind speeds at KACT accordingly for
Monday.
Other than some scattered mid/high level cloudiness streaming
eastward across the region tonight, VFR conditions will persist
through Monday night.
Bradshaw
&&
..SHORT TERM... /Issued 333 PM CDT Sun Mar 18 2018/
/Through Tonight/
Main concern through the short term is the potential for isolated
strong/severe thunderstorms this afternoon and evening.
Much uncertainty still surrounds the next ~8 hours of the
forecast, largely due to the stubborn bank of low clouds that have
been slow to scatter through midday. Ingredients are in place for
some thunderstorms to become severe this afternoon, should they be
able to develop. The uncertainties lie largely on the coverage of
storms and the most favorable location for initiation. A pair of
shortwave troughs are currently moving through the Southern
Plains. A deep surface low resides in southeast Colorado while a
more ill-defined low exists across the San Angelo/Abilene area. A
surface dryline is positioned southward through the surface trough
axis, and a stalled frontal zone is draped from east to west
through North Texas. The warm sector bounded by these features has
begun to destabilize with gradual clearing starting to take place
across our western zones where temperatures have climbed into the
low 80s. When combined with dewpoints in the 60s and very steep
lapse rates aloft (as illustrated by the FWD 18z sounding), these
conditions are yielding a narrow tongue of large SBCAPE values
immediately ahead of a westward-bulging dryline.
As lift increases with height falls from the nearby shortwaves
along with low-level convergence near the boundaries, we should
start seeing attempts at convection. Areas that have cleared
immediately along the dryline may destabilize sufficiently to
break the cap or eliminate it entirely, whereas areas to the east
have remained capped due to the presence of widespread low clouds
and substantially cooler surface temperatures. As a result, am
thinking the greatest potential for convective initiation will
probably be along the dryline and near the triple point
intersection with the stalled front. With strong instability and
50-60 kts of deep layer shear, a supercellular storm mode is
likely. If supercells can develop in this area and move eastward
into the warm sector, they will be capable of surviving as
elevated supercells within a capped environment with primarily a
large hail threat. If some clearing/heating occurs through late
afternoon farther east in the warm sector, a wind/tornado threat
would also accompany storms if surface based instability exists.
The weakly capped environment may actually act to enhance the
severe potential if stronger isolated storms can get going. A weak
cap would suppress weaker convective attempts, allowing stronger
isolated supercells to progress eastward unimpeded.
The above scenario is supported by the most recent runs of the
HRRR and a couple other CAMs. However, on the whole, high-
resolution models remain wildly inconsistent with much
disagreement regarding convective initiation locations and
coverage. Some models are developing practically no convection at
all, which I also have to admit is a realistic scenario if enough
lift/instability is not realized. The most likely scenario is
probably a couple of discrete storms developing across
west/northwest portions of the forecast area which will move
eastward with a potential for large hail. Any convection will move
east fairly quickly and exit the area by midnight or so at the
latest.
Overnight, the dryline/Pacific front boundary will surge eastward
bringing much drier low-level air through the entire region. This
will scour the low level moisture leading to a cooler Monday
morning with some breezy west winds.
-Stalley
&&
.LONG TERM... /Issued 333 PM CDT Sun Mar 18 2018/
/Monday through Sunday/
A strong surface low will move east from northeastern Oklahoma
into Tennessee during the day Monday. The resulting pressure
gradient will lead to gusty westerly winds which will become
northwesterly during the afternoon as another cold front moves
through the region. Skies will be mostly sunny and highs will
range from the upper 60s northwest to around 80 degrees southeast.
The combination of 20 to 25 mph winds with gusts over 35 mph at
times, and minimum relative humidities in the upper teens and 20s
will mean critical fire weather conditions across the western
parts of the forecast area with elevated fire weather conditions
elsewhere.
Wind speeds will be slow to decrease Monday night with northwest
winds 15 to 25 mph prevailing with some gusts over 30 mph. Lows
will be mostly in the 40s.
An upper level ridge will build across the Rockies early to mid
week and then move into the Plains late in the work week as an
upper level low moves east to off the East Coast by late week. This
will result in dry weather across North and Central Texas for the
upcoming work week. It will be cooler Tuesday with highs in the
60s. As a surface high moves east, moderating temperatures will
occur Wednesday through Friday. Highs will be in the upper 60s to
mid 70s Wednesday, 70s to lower 80s Thursday, and mid 70s
northeast to upper 80s west Friday. Southerly winds will increase
Thursday and Friday and despite increasing humidities, elevated
fire weather conditions may occur across the western counties.
With the continued southerly flow and a weakening upper level
ridge next weekend, there will be low chances of showers and
thunderstorms along and east of I-35 Saturday and most of the
region on Sunday. Warmer than normal weather will continue with
highs mostly in the 80s and lows in the 60s.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 56 78 46 65 44 / 5 0 0 0 0
Waco 52 79 45 67 42 / 5 0 0 0 0
Paris 53 73 45 62 41 / 20 0 10 5 0
Denton 51 74 43 65 42 / 5 0 0 0 0
McKinney 51 74 44 63 42 / 5 0 0 0 0
Dallas 56 76 46 66 45 / 5 0 0 0 0
Terrell 53 75 45 65 41 / 10 0 0 0 0
Corsicana 55 77 46 65 43 / 5 0 0 0 0
Temple 51 78 45 69 43 / 5 0 0 0 0
Mineral Wells 50 75 41 65 40 / 0 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday morning through Monday evening
for TXZ100-115-116-129-130-141>143-156-157.
&&
$$
79/66
Area Forecast Discussion
National Weather Service Jacksonville FL
956 PM EDT Sun Mar 18 2018
...SEVERE THUNDERSTORMS POSSIBLE MONDAY AND TUESDAY...
.UPDATE...A few light showers out ahead of the advancing
convective complex to the west has moved eastward into the
Suwannee Valley and interior SE GA this mid evening. The best
instability now resides along and west of I-75 where CAPES are
1000-1500 J/kg. However, recent trends show convection waning
north of the Big Bend with CIN incrementally increasing as the
nocturnal hours progress. As the remnant convective activity
shifts eastward the activity is expected to remain weak with
shower activity being on the increase through the night-time hours
shifting southward with time. The first rain shield that moves
over the region tonight will have some isold convection, mainly
out over the southwest part of the CWA. HRRR showes east Texas
complex that will quickly move into southern Louisiana joining up
with the tail end of the precipitation shield over our region
diving southeastward as a MCS during the pre-dawn hours and very
early daylight hours. In the wake of the MCS, there may be a meso-
high setting up over the western parts of the region during the
late morning and early afternoon, providing a temporary cap with
daytime heating on tap, setting the stages the mid afternoon
through evening as another disturbance approaches the region. Will
have being making some trend up-dates particularly based on the
HRRR and HRRR-X.
&&
.AVIATION...VFR conditions will give way to MVFR conditions as
precipitation shield with some isold convection moves across the
region tonight. A return to VFR will be on tap between 12z and
15z as the showers move east and south of region. A second round
of showers and thunderstorms are expected to develop mid/late
afternoon tomorrow with some intermittent TEMO MVFR conditions
with the stronger thunderstorms between 20z-24z. Light winds
tonight with light south- southwinds developing during the late
morning and afternoon Monday.
&&
.MARINE...High pressure will be S and E of the waters early this week. Weak
low pressure will track eastward north of the waters...maintaining
southwesterly flow over the waters Monday. A stronger low will
pass north of the waters Monday night and Tuesday, producing
stronger southwest winds over the waters which could reach
advisory criteria. A strong cold front will move across the waters
late Tuesday and Tuesday night, likely associated with strong
thunderstorms. Strong northwest winds are expected Wednesday and
Wednesday night with some decrease Thursday, with low pressure
northeast of the area and high pressure approaching from the
northwest.
Rip Currents: Low risk expected with offshore flow through Monday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 62 76 64 82 / 70 70 50 50
SSI 62 73 63 79 / 60 70 60 60
JAX 64 78 65 85 / 80 70 40 60
SGJ 62 77 66 80 / 70 70 40 70
GNV 63 80 66 81 / 90 70 40 70
OCF 62 80 67 80 / 80 90 40 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Cordero//McGinnis
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
1019 PM CDT Sun Mar 18 2018
.UPDATE...
Issued at 1019 PM CDT Sun Mar 18 2018
Recent RAP and HRRR model trends including the 00Z NAM, point
towards an increased potential for enhanced snow accumulations
across central portions of the forecast area. A storm system,
currently centered over southwest Kansas will move east overnight
and Monday. Colder air continues to be drawn into the system with
currently temperatures from the lower to mid 30s north central
and the mid to upper 30s south. The potential exists for total
snowfall accumulations exceeding 3 inches for areas approximately
50 miles east and west of highway 83 before the snow ends Monday
evening.
UPDATE Issued at 655 PM CDT Sun Mar 18 2018
Colder early evening temperatures and latest model trends
indicate an earlier onset of snow along with slightly higher
precipitation chances tonight. The forecast was updated according
to these latest trends.
&&
.SHORT TERM...(This evening through Monday)
Issued at 253 PM CDT Sun Mar 18 2018
The main concern the next 24 hours revolves around the evolution
of a winter storm that will impact the region tonight and
tomorrow. Latest satellite imagery shows cloudy skies with stratus
housing most of the local forecast area with cloud bases 2-4 kft
across the eastern Panhandle and southwest NEB to 400-500 ft
across parts of north central NEB. Regional radar display shows
little in the way of returns outside of echoes moving
northeastward across south central NEB and north central KS.
A shortwave trough will lift out of the Four Corners late today,
close off, and move into northern OK/southeastern KS overnight.
Meanwhile, a strong lee-side low will develop late this afternoon
in eastern CO and will evolve east to southeast KS/northeast OK by
early Monday morning. While there are chances for showers
developing late this afternoon across portions of the Sandhills
attributable to amplifying low-level warm advection and marginal
elevated instability, better chances occur more so mid evening on.
Little change from previous forecasts regarding the atmospheric
environment for this event with it still being relatively
warm based on soundings. Current thinking is will see a
change to mix or snow given dynamic cooling with lift/ascent and
based on the wet-bulb profile evolution tonight. Of which, a
rain/snow mix to snow is anticipated to have worked down as far
south as the southeast-third of the local forecast area by early
morning tomorrow. However, some uncertainty exist with respect to
spatial extent of snow and wintry mix given thermodynamic
profiles. Nonetheless snow amounts are expected to be minor
attributable to character of snow and SLR. Additionally, lift
continues to be somewhat shallow based on omega fields and lower-
tropospheric frontogenesis. Highest expected snowfall is 2 to 3
inches across parts of the western and central Sandhills. In
addition, blowing snow is not expected to be an impact given the
character of the snow and with winds not expected to be strong.
That said, some patchy blowing snow cannot be ruled out early
tomorrow across far western NEB nonetheless. Otherwise, highs will
be generally 10-15 degrees below seasonable values given linger
precipitation, cloudy skies, and colder air filtering in. Highs
are forecast in the mid 30s to about 40 degrees tomorrow.
.LONG TERM...(Monday night through Sunday)
Issued at 253 PM CDT Sun Mar 18 2018
Light snow could linger over northeastern portions (Boyd, Keya Paha,
Rock, Brown, Holt, Garfield, Wheeler) of the forecast area through
about midnight. Otherwise, clearing with temperatures near normal in
the mid 20s Monday night into Tuesday morning.
Tuesday onward...A quick short wave zips by in the northwest flow
that will bring mainly cloud cover but a few sprinkles are possible
across northern Nebraska. Otherwise, a ridge will set up across the
Rockies with downslope or southerly flow taking over at the low to
mid levels, warmer and mainly dry conditions are expected for much
of the week. Stayed with the thinking of the previous forecaster in
keeping temperatures on the warmer side of guidance, resulting in
widespread 50s and 60s for Wed and Thu, widespread 60s to near 70
possible for Friday depending on how much the ridge is beaten down
by an approaching short wave. We can`t rule out some showers along
the east side of the ridge and some enhanced fire weather concerns
in central and western Nebraska. For now, it looks mainly dry next
Saturday with slightly cooler temperatures, back toward normal for
this time of year, and breezy northwest flow. The next chance for
some precipitation will be Saturday night and/or Sunday with some
model disagreement, as expected, this far out.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 619 PM CDT Sun Mar 18 2018
Main aviation concerns will be IFR/lIFR ceilings along with -RA
changing to SN late this evening and overnight. A storm system
currently centered over south central Colorado will move east
into southeast Kansas and southern Missouri by Monday afternoon.
Light to moderate snow is expected across much of western Nebraska
on Monday. Visibilities should mainly range from 1-3sm, except
below 1sm at times from 04z-18z Monday at KVTN. Ceilings should
improve to MVFR after 21z Monday.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Roberg
SHORT TERM...ET
LONG TERM...Allen
AVIATION...Roberg
Area Forecast Discussion
National Weather Service Lake Charles LA
952 PM CDT Sun Mar 18 2018
.UPDATE...
Updated zones and text products for new Severe Thunderstorm Watch
12, which includes the previous watch plus Hardin County as well
as most of our LA Parishes along and north of I-10 through 1 AM.
Several clusters of storms have developed acrs southeast TX this
evening and are now entering western LA. Recent HRRR guidance
suggests this activity will continue to move east, exiting
Avoyelles and Saint Landry Parishes between 05-06Z.
Made some adjustments to POPs and WX for the rest of the evening
and overnight to reflect increased chance of convection as well as
possibility of damaging winds and large hail. Convection has
maintained intensity despite the loss of daytime heating, and KLCH
00Z sounding shows ample energy (MUCAPE ~2700 J/kg) and deep layer
shear available to sustain storms near severe levels this evening.
Over the coastal waters, extended the Dense Fog Advisory to the
current time as at least one site (KSCF) indicates vsbys less than
one mile. Expect dense fog will continue to develop and become
more widespread overnight, persisting until the passage of a cold
front during the day Monday.
24
&&
.PREV DISCUSSION... /issued 711 PM CDT Sun Mar 18 2018/
UPDATE...
Adjusted POPs/WX for early this evening as severe storms to the
west of Tyler County are expected to move into the area within the
next hour. Also included severe wording in grids and zones.
24
PREV DISCUSSION... /issued 600 PM CDT Sun Mar 18 2018/
DISCUSSION...
00Z Taf issuance.
AVIATION...
Watching isolated severe thunderstorms moving east over C TX
possibly making its way over to E TX. Remnant MCV once again could
ignite TSRA over C LA later this evening into the early morning
hours, thus placing VCTS by 02z with tempo group for TSRA from
03-07z. Elsewhere, believe most if any convection that forms will
stay north of the I-10 corridor this evening and overnight. Main
issue here will be lowering ceilings to MVFR to IFR this evening,
possibly reaching LIFR ceilings as well as visibilities towards
09-13z time frame for BPT/LCH/LFT/ARA. The front, with mainly
drier air behind it, expected to move west to east through the
region from 14-18z.
DML
PREV DISCUSSION... /issued 435 PM CDT Sun Mar 18 2018/
DISCUSSION...
Earlier convection over East/South Central LA has push off to the
east and/or dissipated, but has left a residual SFC boundary from
roughly near Jasper, TX to Lafayette, LA. This boundary is
expected to retreat NWD tonight as low level kinematic fields
strengthen with a lead impulse ejecting NE out of OK and the
approach of a more vigorous shortwave trof just east of the Four
Corners. Ample instability/shear is progged to reside along/S of
this boundary the rest of the afternoon and through the evening to
support a conditional risk of severe TSTMS, with that primary
condition being the maintenance/EWD progression of convection
currently underway across E TX. Little in the way of model
consensus has emerged throughout the day on this matter, though
what agreement there is depicts a cluster of TSTMS moving across
interior E TX and Central LA through the evening hours. Recent
coord call with SPC has yielded a SVR TSTM watch for parts of
interior E TX through 11 PM.
Initial front associated with this shortwave trof progged to push
east through the area tomorrow, ushering a much drier airmass into
the region. Small rain chances along and ahead of the front
through the morning, with dry and warm expected by afternoon.
Real push of cooler air to arrive with the passage of a secondary
front Mon night into TUE associated with upstream shortwave trof
progged to dig into the SE CONUS. Cool and dry weather to prevail
mid week amid high pressure at the SFC and NW flow aloft.
Flattening flow aloft and returning low level southerlies will
yield increasing moisture and warmer temperatures to end the
week, with low end rain chances by the weekend as a front sags
toward but stalls just north of the area.
13
MARINE...
A light onshore flow will continue tonight as the northwest Gulf
remains between low and high pressure systems. Patchy sea fog
already over the nearshore coastal waters is expected to become
more widespread and dense later tonight, with a dense fog advisory
in effect for the nearshore waters from midnight tonight through
Monday morning. Areas of fog are expected over the rest of the
Gulf and the coastal lakes and bays. As an upper low advances into
and through the mid Mississippi valley on Monday, a westerly flow
will develop as a surface front passes through. Drier air in the
wake of this front will erode any lingering marine fog. A second
front will push through the coastal waters late Monday night, with
moderate and gusty northwest winds expected in its wake that will
persist through Tuesday. A small craft advisory may be needed
during this time for some or all of the coastal waters. A
southerly return flow develops Wednesday night through the
remainder of the week.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 65 83 50 67 / 70 20 0 0
LCH 69 83 53 70 / 30 20 0 0
LFT 69 82 54 69 / 40 20 0 0
BPT 69 83 53 72 / 30 20 0 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Dense Fog Advisory until 10 AM CDT Monday for GMZ450-452-455.
&&
$$
Area Forecast Discussion
National Weather Service New Orleans LA
806 PM CDT Sun Mar 18 2018
.SOUNDING DISCUSSION...00z balloon went up with no problems. What
it did find was a rather unstable environment still in place.
There is an inversion right around 800mb and could be an issue
later tonight but as of right now we remain uncapped and had a
sfc based cape of 3400 J/kg with sfc LI of -8! The more impressive
aspect is the thick fat cape we have in the mid and upper levels.
Mid level lapse rates are around 7.2 C/km which is rather steep.
At this time the sounding doesn`t show a very favorable tornadic
sounding but given that there is a left over boundary just south
of Slidell any storms riding or crossing that boundary could have
some extra spin to them. Winds have strengthened from this
mornings sounding in the mid and upper levels and there is now a
dry pocket in the mid levels which could enhance the wind risk. We
will do a 6z release tonight to reassess the environment. /CAB/
&&
.PREV DISCUSSION... /issued 719 PM CDT Sun Mar 18 2018/
UPDATE...
Forecast grids and products have been updated to increase chances
for convection later this evening and overnight. The last two or
three runs of the HRRR has forecast a rapid increase in
convection to our west this evening that moves quickly into our
forecast area around midnight and across the area overnight.
Considerable convection is already ongoing across portions of east
and southeast Texas. 11
PREV DISCUSSION... /issued 402 PM CDT Sun Mar 18 2018/
SYNOPSIS...
Latest surface analysis showed a frontal zone from south Georgia
to south Mississippi to central Texas. Surface dewpoint readings
of 65F were south of the frontal zones, mainly over the forecast
area. Upper air analysis showed a ridge axis the Central Gulf
Coast to Dakotas and short wave trough over northern New Mexico
and disturbance on the front side of the wave over Arkansas and
northern Louisiana.
DISCUSSION...
Upper level disturbance on the east side of this shortwave will
pass across the lower and mid Mississippi Valley today and tonight.
This has enhanced shower activity across the forecast area this
afternoon. However, thunderstorm activity has been limited but
coverage of showers remained across the north half of the forecast
area. The short wave over northern New Mexico will track east
through Monday. However, today`s impulse will scour some of the
moisture east tonight. This will leave limited moisture for the
next wave tomorrow. As a result, rain chances decreased a tad to
20 percent on Monday and Monday evening. Associated cold front
will finally reach the forecast area Monday night into Tuesday
morning as a secondary nose of the trough digs south across the
central Gulf Coast. Cooler air will be quickly filtering into the
area during those early morning hours. Should bottom out around
the mid 50s by sunrise Tuesday.
Persistent troughing to the east, northwest flow will be in place
across the forecast area through much of the week. This will keep
temps at to below normal during that time frame and a dry
forecast through the week. A low chance of rain will be possible
the next weekend.
MARINE...
Onshore flow to continue through tonight before becoming
disrupted a bit with a frontal zone settling across the Gulf
states by tomorrow morning. A surge of high pressure pushes the
front into the northern Gulf late Monday night with high pressure
bringing strong northerly gradient winds and building seas to the
coastal waters heading into Tuesday. Small craft advisories will
be needed by Tuesday morning. Winds and seas should begin to wane
late Wednesday.
AVIATION...
Lingering convection near KGPT, KASD, KMSY, and KNEW could produce
brief periods of IFR conditions through around 03z. By 06z, another
round of low ceilings and fog should begin to develop at all of the
terminals. Low ceilings of 500 feet or less and visibilities of
less than a mile will be possible at all of the terminals between
06z and 17z tomorrow. After 17z, the passage of a frontal boundary
should result in increased westerly flow and the clearing of fog and
low clouds. Expect to see MVFR and VFR conditions in place after
18z. 32
DSS code: Blue.
Deployed: None.
Activation: None.
Activities: Monitoring river flooding
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 63 83 51 63 / 50 20 10 10
BTR 64 84 52 65 / 50 20 10 0
ASD 65 82 56 66 / 50 20 10 0
MSY 67 82 58 67 / 50 20 10 0
GPT 65 79 56 68 / 50 20 10 10
PQL 65 79 57 67 / 50 20 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$