Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/09/19
Area Forecast Discussion
National Weather Service La Crosse WI
1103 PM CDT Wed May 8 2019
.SHORT TERM...(This evening through Thursday)
Issued at 235 PM CDT Wed May 8 2019
At 2 PM, a low pressure was located over central Iowa. This system
was producing rain across the Upper Mississippi River Valley.
Rainfall totals range from a tenth of an inch at Medford (Taylor
County) and Mauston WI (Juneau County) to 1.29 inches in Riceville,
IA (Howard County).
For tonight, the models are in good agreement that the 850 mb
moisture transport will move off to the east of the area. In
addition, they show that a dry slot will move into the region. As
this occurs, the precipitation areal coverage will become scattered.
Additional rainfall amounts will range from a 0.25 to 1 inch. With
the RAP continuing to decrease its surface-based and most unstable
CAPES, the thunderstorm chances look lower, so reduced their
probabilities. Low temperatures tonight will range from the mid 30s
to mid 40s.
Thursday looks to be much drier than today. However, with extensive
cloud cover over the region, high temperatures will remain in the
.LONG TERM...(Thursday night through Wednesday)
Issued at 235 PM CDT Wed May 8 2019
The next chance for some rain will be over the upcoming weekend. A
northern stream short wave trough will drop south/southeast out of
central Canada and move across the Upper Midwest. The timing of
this wave looks to be a bit slower and now looks to swing across
the region Saturday night into Sunday. While both the 08.12Z GFS
and ECMWF have been trending stronger with this wave, there are
still some differences on the expected track. The GFS develops an
upper level low with the wave and takes this across northern
Minnesota/Canadian border. The ECMWF also develops an upper level
low and continues to move this to the southeast and reaches the
Ohio River Valley by the end of the weekend. It looks like these
differences will have minimal impact on the sensible weather as
both models push a cold front through with some rain chances
Saturday night into Sunday. Some rumbles of thunder could occur
along and ahead of the front with 200 to 300 J/Kg of ML CAPE
possibly in place over the area.
Additional rain chances will move into the area for Monday night
into Tuesday. The next northern stream system looks like it should
stay well north of the area over Canada but will still push a cold
front across the Upper Midwest. Some showers will be possible as
the front moves through but the chances do not look that good
right now with the main upper level support staying well to the
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1103 PM CDT Wed May 8 2019
IFR to LIFR conditions are expected tonight in low stratus and
areas of drizzle. Low pressure lifts northeast of the area on
Thursday and northwest winds will gradually usher in drier air. We
should see a return to MVFR and eventually VFR conditions Thursday
afternoon into Thursday night.
Area Forecast Discussion...UPDATED
National Weather Service Birmingham AL
850 PM CDT Wed May 8 2019
Late aftn/early evening convection across the region has generally
been on the wave over the past 60 minutes. Still a few isolated
showers noted primarily in the vicinity of a weak boundary
generally along and just east of I-65. Temperatures were quite
mild for early May with readings still in the lower 80s to mid 70s
as of 01z. Current forecast has mins dipping into the mid 60s most
areas by morning and that may be a bit optimistic but probably not
too far off the mark. Most pressing questions concern overnight
cloud cover (stratus development?) and timing of potential
convection on Thursday.
Model guidance remains fairly consistent with increased low level
southerly/southwesterly flow tonight and surge of gulf moisture
northward. Model time sections and soundings indicate likely
stratus development after 08-09z and will continue that trend.
Bigger question surrounds the convective evolution with the large
scale QLCS cross the Mississippi River.
Not certain that any specific guidance has a very good handle on
the timing/spatial extent of this feature (perhaps the HRRR is
catching up to some extent). As the system advances east across MS
it will eventually be encountering a somewhat more hostile
thermodynamic environment along with limited forcing. Having said
that, it`s entirely plausible that the line could maintain itself
at least into the western half of the state early on Thursday with
additional development based on boundary placement.
Previous short-term discussion:Through Thursday
/Issued at 300 AM CT/
Surface high pressure, that has provided us with a few days of dry
weather, is gradually giving way to a storm system moving in from
the west. A few showers have formed in the southeastern portion of
our area, where the best moisture and weak low level convergence
was located. These showers were largely aided by the heating of
the day. Some upscale growth in intensity and coverage is likely
through the remainder of the afternoon, before trending downward
after sunset. Off-the-surface low level winds start to pick up
overnight, which should lead to some stratus development.
Upper level trough in the plains states, with a series of
shortwaves rotating around its base, has caused a large area of
convection to fire up in the ArkLaTex region this afternoon.
Although the primary, linearly-oriented portion of this MCS will
become increasingly removed from its forcing mechanism as it moves
eastward over the next 24 hours, short-term models strongly
suggest that it will be able to maintain itself all the way into
(and likely through) Alabama. Thus, confidence remains high that
much of central Alabama will see a stormy period on Thursday.
However, with the best deep layer shear remaining to our north and
west through the day, continue to agree with prior shifts that
severe weather threat is marginal at best.
/Issued at 300 AM CT/
Thursday night through Wednesday
By Thursday evening and into the overnight hours, the shortwave
has moved to our north and east and the main cold front remains to
our northwest, so we lose much of the forcing needed for
widespread thunderstorms. Therefore, I expect an overall decrease
in coverage of rain and storms through Friday morning.
The overall synoptic pattern doesn`t change much through the
weekend. The persistent ridge across the Southeastern CONUS keeps
the main trough to our west. A few shortwave impulses will move
through, and the lingering frontal boundary from the previous
system slowly approaches the area before stalling. Recent guidance
suggests the cold front could stall across Northern AL. Each
shortwave will lead to increased rain and thunderstorm chances for
most of Central AL Friday, Saturday, and Sunday.
A separate upper level low dips into the Great Lakes region Sunday
evening, pushing a dry cold front southward into the TN Valley by
early Monday. This frontal boundary will finally flatten the ridge
to our southeast, allowing the stalled boundary to push out of our
area by Monday morning, ending rain chances across Central AL.
Another shortwave might slide through towards mid-week, but model
guidance varies substantially on this, so I`ll only mention 30-40%
PoPs in the forecast on Wednesday for now.
00Z TAF Discussion.
Isolated convection was noted across central Alabama early this
evening as a weak surface boundary was situated across the state.
Included VCTS/VCSH at a few sites including KBHM through 02z to
account for current radar trends. However, expect much of the
activity to diminish with the loss of daytime heating.
Conditions will be generally VFR this evening and overnight until
stratus develops/surges northward toward morning. Have maintained
MVFR cigs for several hours late tonight into early Thursday
before showing improving ceilings mid morning. Winds will also
increase on Thursday as the surface gradient begins to tighten and
included gusts at all locations.
Potential for convection will increase as we progress into the
afternoon hours on Thursday. Given some model/timing differences
did not include with this TAF package but will likely need to
introduce some convective potential after 18z tomorrow with later
An approaching storm system will bring enhanced rain chances
starting Thursday afternoon, and lasting through much of the
weekend. There are no fire weather concerns at this time.
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 66 83 66 81 63 / 20 80 40 60 50
Anniston 66 83 67 84 64 / 20 80 50 60 50
Birmingham 69 85 68 82 65 / 20 80 40 60 50
Tuscaloosa 68 85 69 80 66 / 10 80 40 60 60
Calera 67 84 68 81 65 / 20 80 40 60 50
Auburn 66 83 67 85 66 / 20 50 40 40 40
Montgomery 67 86 68 87 67 / 20 50 50 40 40
Troy 66 85 67 87 66 / 20 40 40 40 40
Area Forecast Discussion
National Weather Service Des Moines IA
641 PM CDT Wed May 8 2019
...Updated for 00z Aviation...
.DISCUSSION.../Tonight through Wednesday/
Issued at 315 PM CDT Wed May 8 2019
./Today through Thursday/...
Confidence: Medium to High
System continue to lift north this afternoon with sfc feature
expected to pull main cold front into the area this evening. Main
upper level shortwave will approach by 00z with another round of
showers and thunderstorms developing along the front between 00z and
06z from mainly east of I35 and south of Interstate 80 affecting the
southeast portion of the forecast area. Severe parameters looked
best this afternoon, and window of better opportunity has already
passed with pre-frontal trough that continues to move into eastern
Iowa. The main front will arrive at 00z with some increase in
instability along the boundary; with the HRRR model continuing to
show meager convergence and little redevelopment. The NMM/ARW
suite does indicate some development along the front. Current VISSAT
indicates some cumulus developing in the current warm sector, so
there may be some thunderstorms over the southeast prior to the main
wave in the mid evening hours. By then most of the instability will
have lessened with mainly scattered non-severe thunderstorms over
the southeast. The main low will pull northeast with colder air and
stronger northwest winds pulling in behind the front. Low clouds
are likely to stick around all of Thursday with relatively cold air
expected for the day. After some lows tonight in the 30s over the
north, highs Thursday will only reach the upper 40s northeast to the
lower 50s in the south.
./Thursday Night through Wednesday/...
Clouds will be on the decrease for Thursday night with rather cool
air for early May. Low temperatures are expected to drop into the
mid to upper 30s north and the lower 40s over the south. Winds are
likely to remain in the 5 to 10 kt range. Despite the cold
temperatures, the recent rainfall and wet ground will suppress frost
formation over most of the region. Have left a small area of patchy
frost over the far northwest where skies will have cleared the
longest. The rest of the region will likely have some mid to high
clouds even to near sunrise. Highs Friday will recover in the lower
60s for the day as the high slides over the region and temperatures
recover at H850. The weekend will begin on a nice note with some
sunshine and milder temperatures. Though there is some slight
timing differences between the GFS/Euro with timing and more
significant differences with respect to the location of the late day
Saturday cold front. It appears that a fairly robust upper level
system will drop south into Minnesota/Wisconsin while pulling a cold
front southeast into Iowa by evening. Depending on the timing and
location, there may be some scattered thunderstorms or showers with
gusty winds during the passage of the front.
The remainder of the forecast continues to look dry until late Tuesday
into Tuesday night when another northern stream system drops
southeast with a cold front across the region. Another push of
thunderstorms and cooler air will follow the passage of the front.
Lows Saturday night will range from the lower 40s north to the
mid 40s southeast. Sunday into Tuesday, warming temperatures will
occur with highs beginning in the mid 60s, but stronger warm air
advection will bring 70s back to the area Tuesday. As the front
passes southeast, highs will drop back a bit into the upper 60s to
lower 70s by Wednesday.
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 640 PM CDT Wed May 8 2019
MVFR cigs cover all but southeast Iowa, with a few pockets of IFR
to LIFR cigs over north central Iowa. Patchy fog has also
developed over north central Iowa with IFR visibility. Rain just
north of the Iowa border will continue to push east through the
night, with a stray shower or two possible at KMCW and KALO. A
secondary band of showers is starting to develop over southern
Iowa and may move across KOTM this evening. In addition, winds
will continue to transition to northwesterly, with gust over
25kts possible at times. Conditions will gradually improve through
the day on Thursday.
Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
945 PM CDT Wed May 8 2019
Issued at 623 PM CDT Wed May 8 2019
Warm front continues to cross the area early this evening with
convection now on Illinois side of river. While higher mixed layer
and surface based CAPE values remain south of front, higher shear
values reside to the north. Even so, decent 0-1km shear noted on
latest SPC analysis along convective band that is east of Kewanee IL
and approaching Peoria. Bottom line is still monitoring cells in
central Illinois for any rotation but confidence is low for further
development or a severe weather threat.
Also will need to watch the cold front approaching from the west for
any development, but as surface winds veer, shear diminishing and
lack of any strong forcing will likely limit this, which is backed
by latest mesoscale models.
Issued at 340 AM CDT Wed May 8 2019
As of 3 AM, SPC Mesoanalysis showed 850mb WV transport was
increasing across the Mid to Upper Mississippi Valley. Low to mid
level warm air advection will continue to produce scattered showers,
and eventually, isolated thunderstorms into early this morning. So
far tonight, temps were in the 40s and 50s, and winds have been
gusty around 25 mph out of the east.
An upper trough was located over the Western U.S. with an embedded
500mb vorticity max over New Mexico. Convective activity covered a
large portion of the Plains downstream of the large-scale trough.
GOES IR satellite loops displayed an expansive area of convection
with one large MCS or squall line from eastern Kansas into southern
Oklahoma. Much of the precipitation in NE Kansas associated with the
MCS was already stratiform in nature, although still moderate to
heavy in intensity, and had a cyclonic circulation on radar. This
MCV, or area of convectively induced low pressure, will track
northeast toward Iowa later today.
.SHORT TERM...(Today and Tonight)
ISSUED AT 340 AM CDT Wed May 8 2019
Overview: There is a Slight Risk for severe thunderstorms per the
latest outlook from the Storm Prediction Center. The primary threats
with the strongest storms are damaging winds and isolated tornadoes.
The most likely timing for scattered storms is between 2 and 8 PM
from SW to NE through the forecast area. There is also a Slight Risk
for excessive rainfall.
As mentioned in the Synopsis, scattered showers and isolated storms
are anticipated this morning. Then a break in the precip is possible
as the warm air advection wing shifts north. Additional rounds of
showers and storms are likely this afternoon with the arrival of a
surface warm front. The key here is coverage will be scattered.
Shear, both deep layer and low-level, will be high. The 0-6 km
vector is 45+ kts and 0-1 is 30+ kts. Confidence is much lower on
the degree of instability that can be attained due to effects of low
clouds. Not surprisingly, forecast soundings are indicative of a
high-shear low-CAPE setup. The instability is narrow, low-level
shear is extremely strong, and LCLs are very low. Assuming we can
get a few convective cells to form (per the HRRR and 3km NAM), the
likely mode is low-topped supercell/hybrid QLCS.
Flash flooding is something to watch for in areas that receive
repeated rounds of heavy rain. Right now, the thinking is this will
be a fairly isolated threat because forecast storm motion is 35-40+
mph. Yet PWATs should peak near 1.6", so the atmosphere will be
supportive of very heavy downpours. Opted not to issue a Flash Flood
watch on this shift due to what is expected to be an isolated
threat. Day shift still has time to analysis morning models and obs
before the heavier rain late this afternoon into tonight and could
go with a watch if needed.
Heading into tonight, another surge of moisture tied to the parent
surface low and mid-level vort. max may bring more rain to the area.
Models aren`t in very good agreement on the placement with this
round, slightly favoring the eastern two-thirds of the CWA. Uttech
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 340 AM CDT Wed May 8 2019
Cold front will be crossing western counties early on Thursday
and should exit rest of CWA by late Thursday morning taking
the precipitation with it. Temperatures ahead of the front in
brief warm sector residence should spike into the 60s along
and east of the Mississippi River, with lower 70s possible far
east. Meanwhile, temperatures will be already falling through
the 50s in the western counties in post-frontal cold advection
on gusty NW winds, which will follow passage of the cold front
further east. By afternoon temperatures should level off into
the upper 40s to mid 50s, well below normal and more typical of
Thursday night into early Friday...
There is a bit of a signal for trace to a couple of hundredths of
an inch, as additional energy ripples up in the flow with assist
from left exit lift quadrant of H25-30 jet. PoPs kept at just
20 percent, as lift will be battling incoming low level subsidence
and drying attendant to building ridge. Otherwise, continued
below normal temperatures with 40s mainly to start off Friday,
and highs reaching the upper 50s to lower 60s.
Friday night through Sunday night...
Amplifying eastern Pacific ridge will assist in sharpening upper
level troughing over the central CONUS this weekend. This will
lead to a continuation of below normal temperatures despite some
moderation during the period, with mainly 40s for lows and 60s
for highs. Modest PV anomaly is shown by models to dig south
across the Upper Midwest this weekend, and will bring scattered
showers by Saturday night into Sunday. This could result in
cooler highs by a few degrees from the forecast on Sunday.
Rainfall will be spotty and light (less than 0.25 inch) and
will not have any impact on river levels. Marginal mid level
lapse rates and largely unfavorable nocturnal timing should limit
Monday through Tuesday...
Models in general agreement on shifting the Pacific ridge into
the High Plains, which along with some downslope component to
flow should bring a warming trend with highs recovering mostly
into the 70s. Some indications of another digging northern stream
shortwave by Tuesday, although timing and track uncertainties
do exist. However, if this system were to speed up it could have
an impact on lowering highs for Tuesday.
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
ISSUED AT 623 PM CDT Wed May 8 2019
Variety of aviation conditions this evening with approach of short
wave trough and associated surface low. Bulk of the convection has
passed the TAF sites but still seeing a mix of VFR and MVFR
conditions near the warm front. Main challenge will be timing extent
of IFR and MVFR ceilings as surface low lifts northeast and sweeps
in stratus field behind system heading into the overnight hours and
Thursday. Will also be watching wind shift as cold front approaches
from the west.
Have banked on a period of IFR conditions for most sites as storm
system exits and winds continue to veer to the northwest. Could see
some improvement in ceilings later Thursday but plenty of cloud
cover upstream in wake of this system to deal with.
Issued at 943 PM CDT Wed May 8 2019
Little change to the forecasts tonight. As such earlier discussion
is still relevant and is attached below.
River forecasts issued this morning have come in much lower than
those last evening as a result of a northward shift in the
forecasted rainfall area; which is now expected over MN and WI.
The warnings for Kalona, Marengo, Conesville, St Francisville, and
Augusta have been cancelled; as they are not expected to reach
their respective flood stages.
Minor flooding will continue at Oakville, Joslin, and Colmar.
Moline will continue to drop today, falling below the moderate
flood stage level late tonight. DeWitt is forecast to start to
rise today, and crest at the moderate flood stage of 11.5 feet
Friday. If expected rainfall amounts upstream of DeWitt are not
realized, then it may not reach this level.
As for the Mississippi River, overall the downward trend will
continue with a slight leveling off or slight rise at both Dubuque
sites. Bellevue is currently expected to fall below its flood
stage Sunday. From Bellevue to Keokuk, a steady fall is expected
to continue, with the possibility of the rate of fall slowing this
weekend into next week as the rainfall from MN and WI works its
way downstream. Gregory Landing is forecast to see a slight rise
Thursday afternoon and evening as a result of the heavy rains over
southeast Iowa and west central Illinois from earlier this week.
Overall, negligible rainfall amounts pertaining to the MS River
forecast are expected beyond Thursday.
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
947 PM CDT Wed May 8 2019
A few changes were made to the forecast, but in general, the
previous package is in good shape.
After an active day weather wise...we will have a brief respite
tonight from widespread rainfall. However, there are two areas
that we are watching for a rain/storm potential through the
overnight hours. Upstream radar observations indicate a lone
convective cell--- that has had a history of producing golf ball
sized hail in Oklahoma---continues to slowly weaken and slide
southward. This storm appears to be along a wavy front that is
located just north of a Wichita Falls to Oklahoma City to Kansas
City line. This front will move slowly towards the south during
the overnight hours. I expect this activity will continue to wane
as it moves off the corridor of higher instability that developed
where clouds cleared early in the day. That in mind, I`ll
advertise a 20 PoP across the western Red River Valley with the
expectation that only a marginal severe weather risk will exist
should this storm continue to progress towards the south and east.
The other area worth mentioning is across the Brazos Valley where
radar mosaic indicates an uptick in convective elements. There
appears to be some decent WAA based on the radar
presentation...and RAP 850-700mb temperature fields confirm this.
I`ll keep a 30-40 PoP across this area with a mention of isolated
storms given that low level flow may ramp up even more. At this
time, the severe weather risk looks marginal given that the
earlier MCS has likely utilized most of the available potential
energy. Still...we will monitor trends for a marginal severe hail
risk given the increasing low level wind field.
The final change was to beef up fog wording across the area.
With temperature/dewpoint temperature spreads already less than 5
degrees for most of the area coupled with recent rainfall---
thereby adding in an additional source for upward moisture flux
into an already moist PBL---feel that guidance which advertises
foggy conditions are on the right track. In addition, low level
flow will turn towards the east in response to the broad surface
low out to the west. Have added a mention of areas of fog for
parts of the FA with patchy fog for the remaining areas. It`s not
out of the realm of possibility that a dense fog advisory may be
needed for some areas, but confidence at this time precludes
posting one now.
.AVIATION... /Issued 732 PM CDT Wed May 8 2019/
/00 UTC TAF Cycle/
Concerns---Ceiling and visibility trends through the TAF cycle.
FROPA timing and strong north post-frontal winds.
The biggest challenge in this TAF set will be the evolution of
cigs/vsby. MVFR stratus this evening is expected to erode from
west to east (though some thinning of the stratus deck was noted
east/southeast of D10). While the timing is a little uncertain,
it`s reasonable that FTW...AFW and ACT will see VFR in the next
2-4 hours. GKY...DAL and D/FW may see a more prolonged period of
cigs around FL015 through the evening push...but a brief period of
VFR seems possible just before midnight at these TAFs. Upstream
showers and storms should remain to the northwest of D10 airspace
as the instability profile is more favorable across SW Oklahoma
and adjacent parts of western North Texas. Impacts to the Bowie
cornerpost and northbound departures are still possible.
My confidence in cig/vsby forecast overnight is low to medium, so
some changes based on the newest guidance and observations may be
needed. At this time, I believe that low level flow will slowly
back to the east with the approach of a broad low. The increase
in moisture from East Texas coupled with the added moisture flux
from recent rainfall should be enough to facilitate BR---possibly
FG---and IFR to possibly LIFR cigs. I`ve introduced IFR vsby/cigs
at all TAFs. Poor flying conditions will invade from the east with
AFW and FTW likely being the last two sites to become IFR. Occasional
LIFR cigs/vsby are possible at all TAFs. Brief instances of FG
are more likely at ACT where conditions may be more conducive.
Poor flying conditions will continue for the Thursday morning
push with light and variable winds swinging around to the WNW. A
cold front will plow southward through all TAF sites by 2200 UTC
Thursday with sustained winds near or just under 20 knots. Some
gusts as high as 30 knots are not out of the question. VFR is
expected to return after FROPA for the Thursday evening push.
.SHORT TERM... /Issued 321 PM CDT Wed May 8 2019/
The leading edge of thunderstorms has moved east of the region,
with only lingering showers along a Paris to Hearne line. Dense
cloud cover associated with the system will continue to track
east, and the far western counties may see some sunshine before
the day ends.
While most of the region will remain rain free through the evening
and overnight hours, high res guidance has suggested some
activity lingering across our far eastern counties this evening
and tonight. To account for this potential, painted some slight
chance PoPs across this area. Winds will become light overnight,
and in combination with the recent rainfall, clearing skies, and
moist environment, the development of patchy fog will be possible
after midnight. The general location of development is along and
east if I-35 and along and south of I-20, but this may need to be
adjusted based on evening observations and trends. One limiting
factor may be the quick return of low clouds towards day break.
Guidance has also suggested some light showers may develop ahead
of a cold front across the northwest late Wednesday night into
early Thursday morning. The cold front will approach the
northwestern counties by early Thursday morning.
.LONG TERM... /Issued 321 PM CDT Wed May 8 2019/
/Thursday through Next Week/
Precipitation associated with one of several shortwave
disturbances will have pushed off to the east at the start of the
period. A cold front will follow closely behind, moving through
the northwest counties around daybreak and clearing the southeast
counties late Thursday afternoon. Spotty showers may accompany the
front but significant convection is not expected. High
temperatures will remain in the lower to middle 60s across the
northwestern third of the region behind the front, but should
reach the lower 80s across the southeast prior to the front`s
As the cold front reaches the Gulf Coast, the next upper level
low will be deepening across Southern California. The resulting
upper level pattern will place southwest flow overhead. An initial
shortwave lifting out of the Rio Grande Valley will help generate
a region of enhanced isentropic lift across Central Texas, leading
to the development of elevated showers and isolated thunderstorms
Thursday night. POPs will be limited to the southern third of the
region initially, with precipitation shifting north to near the
I-20 corridor on Friday. A second disturbance will spread
precipitation even farther north late Friday night into Saturday.
Thunderstorms will likely remain of the isolated embedded variety,
but elevated instability should be sufficient for a few hail-
The primary concern during the Friday-Saturday precipitation
event will be the aggravation of ongoing river flooding across the
region, particularly in the Trinity river basin where many sites
are already experiencing river levels above flood stage. Minor
flooding in both rural and urban areas can also be expected each
day, primarily south of the I-20 corridor. Otherwise, it should
merely make for a cool and damp start to the weekend with Friday
and Saturday high temperatures mainly in the 60s.
Precipitation will exit to the east late Saturday night along with
the aforementioned shortwave disturbance, giving way to ridging
across the area on Sunday. This should make for a pleasant second
half of the weekend with dry conditions and high temperatures in
the mid and upper 70s Sunday afternoon.
The West Coast low will make a slow and steady approach starting
Sunday, moving across the Four Corners region on Monday and into
the Texas Panhandle on Tuesday. An upper ridge should keep the
area rain free on Monday, but a lead shortwave will bring a round
of showers and thunderstorms to the area Monday night into
Tuesday. Rain chances should continue late Tuesday into Wednesday
as the main upper low moves across the area. Steep lapse rates
will produce a chance of a few strong to possibly severe storms
with large hail the main threat, though at this time it`s far too
early to get into specifics. An upper ridge should bring another
reprieve during the second half of next week.
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 66 74 53 69 59 / 10 10 20 30 70
Waco 65 79 54 67 60 / 5 10 40 50 70
Paris 63 76 52 67 58 / 20 10 10 30 60
Denton 62 69 51 69 57 / 20 20 10 20 70
McKinney 63 73 51 68 58 / 20 10 10 30 70
Dallas 66 76 53 69 60 / 10 10 20 30 70
Terrell 66 80 53 70 59 / 10 10 20 40 70
Corsicana 67 81 53 67 60 / 10 10 40 50 70
Temple 66 82 54 66 60 / 5 20 50 60 70
Mineral Wells 60 67 48 66 54 / 10 10 10 20 70
Area Forecast Discussion
National Weather Service Huntsville AL
908 PM CDT Wed May 8 2019
Issued at 908 PM CDT Wed May 8 2019
A rather warm evening is in progress after a hot afternoon and our
first 90 degree day in HSV for 2019. Earlier isolated showers in
northeast AL are dissipating. A strong-severe QLCS was making quick
progress east across the I-55 corridor in MS. At present rate, some
of this activity will reach northwest AL in the next 3-4 hours, but
likely in a much weakened state. Latest HRRR runs have been showing
this reaching northwest AL into southern middle TN, but then
weakening/dissipating quickly as well. Will introduce a low PoP to
account for this activity, however, expecting either showers or
general thunderstorms at this time. Then, will keep the PoP for late
tonight entering northwest AL with a secondary area of
showers/thunderstorms expected to develop in LA/AR and spread rapidly
northeast Thursday morning. The HRRR is more in line with the 18Z
FV3 in faster timing of a secondary QLCS on Thursday. The 00Z NAM is
also indicating an earlier arrival of the line as well, but also
seemingly weakening as it moves east. Have adjusted PoPs through
Thursday for a bit faster timing, but still agree with marginal
severe weather risk at this point.
.SHORT TERM...(Thursday through Friday)
Issued at 255 PM CDT Wed May 8 2019
Cold front will continue to approach the region Thursday morning,
sparking a gradual uptick in convection from west to east across
North Alabama and Southern Middle Tennessee throughout the day. With
some decent warming in the morning, we should reach the upper 70s to
lower 80s, meaning that some appreciable destabilization will occur
by the afternoon. Despite the weaker bulk shear values, SBCAPE as
high as 1000-1500 (perhaps locally higher) if we can sufficiently
warm. Sounding profiles are fairly moist, indicative of a greater
rainfall threat than convective winds or hail. Still, enough shear
will exist (along with forcing from the front) to allow for some
organized clusters of thunderstorms, and thus a strong to marginally
severe thunderstorm risk during the afternoon and evening hours
across the entire area.
The initial wave of convection will shift to the east of the area
gradually Thursday night. However, with the front stalled across or
near the region on Friday, additional rounds of convection are
expected. PWATs increase as high as 1.6-1.7 inches, meaning locally
heavy downpours will be the main concern with this activity. The
tall, skinny CAPE profiles, enhancing the updraft potential and the
sustainability of this convection. Thus, think that that general
thunderstorms are likely, but the threat for severe weather will be
low. Abundant cloud cover will significantly limit temperatures and
we`ll likely remain in the 70s for the entire day, a bit cooler than
what we`ve seen earlier in the week.
.LONG TERM...(Friday night through Tuesday)
Issued at 255 PM CDT Wed May 8 2019
With the aforementioned boundary in place across or very near the
Tennessee Valley, additional rounds of moderate to heavy convection
are expected this Mother`s Day weekend -- with storm total amounts of
2-3" of rain possible. Soundings continue to exhibit the tall, skinny
CAPE profiles, with more modest shear profiles (limiting the threat
for strong thunderstorms). However, with a boundary in place (with
the mean flow being from the SW), the threat for training and locally
heavy rainfall and hydrologic issues will exist (mainly in the form
of areal flooding and minor issues on rivers by late this weekend).
PWATs increase to around 1.8-1.9 inches, well within the 90th
percentile for this time of year. Thus, we`ll need to watch hydro/QPF
trends in the coming days. The dense cloud cover and widespread
shower and thunderstorm activity will mean below normal temperatures
for Mother`s Day weekend, with highs in the 70s.
Beyond the weekend, an upper-trough will swing into the Ohio and
Tennessee Valleys, kicking out the front and promoting continued
cool, but much drier weather for Monday and Tuesday. Highs in the mid
to upper 70s will continue, despite the sunshine early next week.
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 515 PM CDT Wed May 8 2019
VFR flight weather conditions are expected through tonight. Ceilings
at or above 150agl will overspread the area by 09Z. Isolated
thunderstorms will be possible from 09-13Z, but the chance remains
too low to include in the forecast at this time, so opted for VCSH.
However, a line of showers and thunderstorms is expected to sweep
west to east across the area during the morning into the afternoon
ours. The gust front/precipitation should arrive at KMSL between
13-16Z and at KHSV from 15-18Z. Gusty winds of up to 40kt and heavy
rain reducing visibility briefly to at least MVFR (3-5sm), but
possibly IFR at times. The rainfall should diminish by 19-21Z with
ceilings rising to ~070agl or above.
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Area Forecast Discussion
National Weather Service Elko NV
302 PM PDT Wed May 8 2019
.SYNOPSIS...Afternoon showers and a few thunderstorms are expected
in eastern Nevada through this evening, otherwise dry conditions
will prevail. More widespread showers will arrive Thursday,
especially in central Nevada, along with isolated afternoon
thunderstorms. Temperatures begin to warm over the weekend with
active weather persisting across central Nevada.
.SHORT TERM...Tonight through Friday
Longwave trof is currently in the center of the U.S. and
shortwaves continue to ride down along the backside of the trof.
Eastern Nevada is on the very western periphery of this afternoon,
which will bring some shower and isolated thunderstorm activity
through the evening. The RAP and HRRR are bringing this activity
further west then the model blends, which looks in tune with
satellite and water vapor trends, so precipitation chances were
extended a bit westward through the evening.
The longwave trof starts to split tonight and the southern
portion retrogrades on Thursday, heading back towards the
California coast. As it passes by Nevada, it will return showers
to the state. The showers will start in northeast Nevada on
Thursday morning and spread southwestward during the day. Showers
will continue in central Nevada on Thursday night through Friday
as northern Nevada dries out. Storm totals through Friday will be
greatest in central Nevada. Due to the convective nature of the
precipitation, totals will vary, but could exceed a half inch of
QPF in southern portions of northern Nye county.
It will be a bit breezy through Friday, with strongest wind in
Humboldt County, where the gradient is tightest. Valley gusts
will be around 30 mph or so there, with stronger higher elevation
Another cool night is expected tonight, with lows in the 30`s for
most valleys, with some 20`s for the colder locations.
Temperatures will cool a little more by Friday morning, especially
in northern Nevada where skies begin to clear out. Highs will be
in the 50`s and 60`s both Thursday and Friday in the northeast to
.LONG TERM...Friday night through next Wednesday.
Closed low circulation offshore from SoCal places a deformation
axis across Nevada. The northern Nevada will be dry, but some
moisture rotates into southern Nevada with Highway 50 being the
northern extent of this moisture field. The best chance for
showers or afternoon storms will be Saturday afternoon and again
on Sunday afternoon. This coincides with the slow eastward
movement of the upper low that tracks toward Arizona.
By next Monday and Tuesday, the upper low will have moved
downstream. However a thermal surface low will be centered over
northern Nevada, combined with afternoon instability will generate
convective showers each day. Storms will be concentrated over the
higher terrain, but a few storms will impact valley locations.
Confidence is not too high for Wednesday regarding timing for a
surface front that may sweep across the region. The front may
trigger additional storms on Wednesday. At any rate, the long term
period will have above normal temperatures for mid May with the
potential for showers/storms each afternoon and early evening.
Showers may be in the vicinity of KEKO (through 03Z) and KELY
(through 08Z) this evening. Isolated showers will be short lived
as they move toward the south and dissipate overnight.
Additional showers will develop Thursday afternoon with a few
thunderstorms. All TAF sites will be in the vicinity of
.FIRE WEATHER...Showers and isolated afternoon thunderstorms will
be confined mainly across eastern Nevada this afternoon and
evening. Gusty outflow winds and a few cloud to ground strikes
are possible. More widespread showers and thunderstorms will
return to the state Thursday as a weather disturbance moves
through the region. Precipitation will continue in central Nevada
on Friday as northern Nevada dries out. Gusty winds will be
strongest in FW Zone 467 both Thursday and Friday as the gradient
.HYDROLOGY...Streams and rivers continue to fall across northern
Nevada. Minor flooding is still occurring at the Humboldt River
at Comus but is expected to fall below flood stage tonight or on
Thursday. A warming trend is expected this weekend.
Area Forecast Discussion
National Weather Service Shreveport LA
948 PM CDT Wed May 8 2019
Scattered showers and isold tstsm redeveloping quickly in the wake
of svr mcs that moved across area durg aftn...mainly along and
south of I-20. Some of this convection may become more intense as
atmosphere moistens in mid lvls and destabilizes. Western portions
of area, especailly towards the East TX lakes area, may see areas
of fog redeveloping where both ground and boundary layers remain
saturated. Amount of fog would depend on persistence of
redeveloping convection, and amount of mid lvl cloud cover
streaming newd back into area. Overnight pops ranging from 20
percent west to 60 percent east./07/.
AVIATION... For the 09/00z TAFs, a line of convection will
continue to affect portions of North Central Louisiana for the
first couple of hours of the TAF cycle. Storms may redevelop
farther to the northwest across Southwest Arkansas, Northwest
Louisiana, and East Texas, especially after 09/06z. This next
round of convection should completely exit by early Thursday
afternoon, but more scattered storms are expected to develop
immediately ahead of a cold front that will be advancing southeast
across the area beginning around 09/21z. Otherwise, flight
conditions should deteriorate through the night as MVFR/IFR
ceilings are expected at most terminals until late Thursday
morning and into Thursday afternoon when ceilings should very
slowly lift back into the VFR range.
PREV DISCUSSION... /issued 445 PM CDT Wed May 8 2019/
SHORT TERM.../Tonight through Thursday Night/
Strong to severe QLCS continues to push east across Southern
Arkansas, Northern Louisiana, and Deep East Texas. CAPE values of
1000-2000 J/kg are present just ahead of the complex, but
instability begins to decrease with eastward extent into Northeast
Louisiana. However, surface winds have backed over Southern
Arkansas and Northern Louisiana, with winds from the southeast at
10-15 kts with gusts of 20-25 kts. This is helping to yield 0-1
km SRH values of 200-350 m2/s2 ahead of the QLCS. Therefore, a
threat for QLCS tornadoes will likely persist for several more
hours. In addition, multiple bowing segments have developed along
the complex, which will also pose a threat for damaging straight-
Interestingly, some of the CAMs, such as the HRRR and the 3km NAM,
are suggesting the QLCS will rapidly weaken after 00z. Given the
environment ahead of the QLCS, I think the complex will likely
maintain itself longer than the CAMs suggest.The HRRR also
redevelops more scattered convection across East Texas during the
01z-02z time frame this evening. There is a large area of light to
moderate rain ongoing behind the QLCS over East Texas, so I`m
skeptical that the atmosphere will have enough time to sufficiently
recover to more storms to develop so soon. However, latest radar
loops show more isolated storms separated from the convection
heading northeast towards Deep East Texas. This may be what the
HRRR is depicting. In addition, a strong low-level jet remains in
place to provide moisture and shear for severe thunderstorms.
Therefore, Tornado Watch #153 will be maintained for a few more
hours, but will continue to be evaluated.
A threat for severe weather will likely persist in some form
through tonight and into at least midday Thursday. Model guidance
still suggests another QLCS will develop ahead of the approaching
cold front during the overnight hours and will move east into
Southern Arkansas and Louisiana around 12z Thursday morning before
exiting by early afternoon. Yet more scattered storms are possible
immediately ahead of the front late Thursday afternoon and
evening, but widespread severe weather is not anticipated with
Given the relative lull that is expected on Thursday, no changes
were made to the Flash Flood Watch. A new watch may be needed for
the later heavy rain event that will occur Friday and into the
weekend, especially based on the rainfall received between now and
Thursday night. More details on that time period are below.
LONG TERM.../Friday through Tuesday Night/
Sfc cold front front to be just s of the region Friday morning, but
the 850 mb front will be draped across the srn and ern portions of
our region from sw to ne. Meanwhile, a compact disturbance is fcst
to be movg newd across Central and SE TX in swly flow aloft. Heavy
rainfall is likely to develop as this disturbance lifts newd along
the 850 mb front. The sfc front will also eventually lift nwd,
especially as a sfc low/trof axis develop along the TX Gulf
Coast/Deep E TX Friday night. Model output differs quite a bit with
regard to timing of waves of convection, but it seems likely that
multiple rounds of tstms will move across our region through
Base of the nrn stream upper trof will finally force the cold front
through and bring a brief pd of dry weather to the region Sunday
night into Monday. However, another srn stream upper low will
approach from the w for Tuesday, bringing swly flow aloft and more
chances for rain. /12/
.PRELIMINARY POINT TEMPS/POPS...
SHV 71 83 60 70 / 50 60 50 70
MLU 71 85 66 74 / 60 70 70 70
DEQ 66 79 52 69 / 40 40 20 40
TXK 69 81 56 67 / 40 50 30 60
ELD 69 83 60 69 / 60 60 50 70
TYR 70 82 54 69 / 20 30 50 60
GGG 71 82 56 70 / 40 50 50 70
LFK 72 83 61 73 / 40 60 70 90
AR...Flash Flood Watch until 7 AM CDT Thursday for ARZ050-051-059>061-
LA...Flash Flood Watch until 7 AM CDT Thursday for LAZ001>006-010>012.
OK...Flash Flood Watch until 7 AM CDT Thursday for OKZ077.
TX...Flash Flood Watch until 7 AM CDT Thursday for TXZ096-097-108>112-
Area Forecast Discussion
National Weather Service Tucson AZ
322 PM MST Wed May 8 2019
.SYNOPSIS...A few showers and thunderstorms northeast of Tucson
this evening. Dry Thursday then a series of stronger systems will
bring a chance of showers and cooler temperatures to southeast
Arizona Friday into Monday.
.DISCUSSION...Regional doppler radar was depicting isolated to
scattered showers and thunderstorms across the northern half of
the state associated with an upper level low trof moving across
Arizona this afternoon. Earlier this afternoon a few of these
storms in Yavapai county produced dime size hail. As the trof axis
pushes across eastern Arizona, storms will be moving across
eastern Pinal, Graham and Greenlee counties, or mainly north of a
Mammoth to Safford to Clifton line. Latest HRRR run has activity
ending by around 11 pm. Mostly clear overnight with lows similar
to this morning with isolated spots of Santa Cruz and Cochise
counties being in the upper 30s.
Thursday will see increasing high clouds as flow aloft turns to
the southwest in advance of an upper level trof developing Nevada
and central California. Highs mostly 3-6 degrees warmer than
Thursday night into Friday will see a closed upper low developing
over central California. Models suggesting a few weak southern
stream upper level disturbances will move through the base of the
upper low across Baja and Sonora Mexico and bring a chance of
showers and thunderstorms to mainly the eastern half of the
forecast area Friday and Friday night. Highs on Friday 7-10
degrees cooler than Thursday.
The above mentioned closed upper low will migrate to off the
southern California coast on Saturday and then open up and lift
across the state Sunday into Monday. Shower activity on Saturday
mainly NE of Tucson with more areal coverage expected Sunday into
early Monday morning with lingering showers NE of Tucson Monday
afternoon. High temperatures will be pleasantly cool for May with
readings 10-13 degrees below normal.
Trof axis east of the state on Tuesday but enough moisture around
over the Mogollon Rim for a chance of showers across the White
mountains. Highs on Tuesday around 5 degrees warmer than Monday.
Dry and warmer next Wednesday under weak ridging aloft. Highs will
be right around normal for mid-May.
.AVIATION...Valid through 10/00Z.
Clouds generally SCT-BKN 8-12k ft then gradually dissipating
overnight. High clouds will begin to move in Thursday morning into
the afternoon. ISOLD -SHRA/-TSRA possible northeast of Safford this
afternoon into the early evening. Surface wind W/NW 10-16 kts with
gusts 20-25 kts this afternoon into the early evening. Winds will
diminish after 09/03Z becoming gusty out the southwest again
Thursday afternoon. Aviation discussion not updated for TAF
.FIRE WEATHER...Continued below normal temperatures today with
breezy winds, especially eastern areas. Meanwhile, above normal
moisture values for this time of year today with few showers and
thunderstorms possible for the White Mountains this afternoon and
evening. A brief warmup to normal temperatures Thursday with a S/SW
breeze. Friday through Monday a large area of low pressure will very
slowly move across the southwest resulting in cooler than normal
temperatures and isolated to scattered shower/thunderstorm activity
through the four day period. Drier weather is expected to return by
the middle of next week with temperatures gradually returning back
to normal levels.
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