Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/18/19
Area Forecast Discussion
National Weather Service La Crosse WI
615 PM CDT Wed Apr 17 2019
.SHORT TERM...(This evening through Thursday)
Issued at 254 PM CDT Wed Apr 17 2019
There remains a small threat for a strong to severe storm early this
evening across portions of northeast Iowa into southwest Wisconsin.
The area of low pressure is still expected to track northeast into
northern Wisconsin this evening. This should allow the warm sector
to briefly advance north into parts of the region with dew points
quickly climbing into the upper 50s to lower 60s creating surface
based CAPEs of 500 to 1000 J/kg. Ample 0-3km shear, up to 40 knots,
will reside over the warm sector with about 20 to 25 knots of this
in the 0-1 km layer. If any storms can become rooted in the boundary
layer, they could produce a brief tornado. However, forecast
soundings from several runs of the RAP suggest there is a very short
1 to 2 hour window where the cap might erode long enough for the
storms to become surface based. Even if they do, the CAPE profile
still does not all that favorable being very skinny and suggesting
the updrafts may not be strong enough to survive for very long.
Overall, this continues to be a very marginal severe weather threat
but one that will have to monitored until the cold front moves
through early this evening.
Once the low goes by the area, low level cyclonic flow will set up
for Thursday. This combined with the main upper level trough could
be enough to generate some shower across parts of the region and
have kept in some small rain chances for that.
.LONG TERM...(Thursday night through Wednesday)
Issued at 254 PM CDT Wed Apr 17 2019
The 17.12z GFS/ECMWF/NAM are in decent agreement in digging upper
level trough over the Ohio River Valley Thursday night into
Friday and closes off upper level low over the southeast United
States Friday night into Saturday. The eastern part of the
forecast area remains on the western periphery of the upper level
trough and produces a small chance of rain showers across
southwest/central Wisconsin Thursday night. Then...upper level
ridge builds into the Northern Plains States/Upper Midwest Friday
into Saturday. Subsidence underneath ridge will provide dry
weather across the forecast area. Cooler temperatures filter into
the Upper Midwest briefly behind upper level trough with low
temperatures falling into the 30s Thursday night across the
forecast area. Warmer air advects into the forecast area
Friday/Saturday...with the 17.12z GFS/NAM/ECMWF showing plus 12 to
plus 17 degrees celsius at 925mb by 00z Sunday. High temperatures
should climb into the 60s and possibly into the lower 70s in a
few locations Saturday.
Main forecast concerns Saturday night into Wednesday are
precipitation chances through the period. The 17.12z GFS/ECMWF/GEM
suggest overall pattern becomes west to east zonal flow over the
northern tier United States. The deterministic models are not in
agreement in the strength of each piece of energy embedded in the
west to east zonal flow aloft. This will have impacts on timing
of precipitation chances and how widespread the showers or rain
will be across the area through the period. Temperatures through
the period will be near normal...with highs climbing into the
middle 50s to middle 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 615 PM CDT Wed Apr 17 2019
Cigs: low saturation slated to hold fast across the region through
most of THU with satellite imagery showing expansive cloud shield
through the northern plains. Should see minor improvement in heights
through the TAF period, but probably not VFR until it scatters out -
more likely Thu evening.
WX/vsby: shra/ts likely cleared east of KRST around 00z, lingering
at KLSE til 02-03z. Not anticipating any br/fg post the showers as
winds pick up, sfc Tds start to dry out with cold front pushing east.
Winds: direction will quickly swing northwest/north by 00-02z with
passage of a cold front. Periodic gusts through the period. Should
see some slackening by Thu evening with approach of weak high
pressure.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...Rieck
Area Forecast Discussion
National Weather Service Bismarck ND
943 PM CDT Wed Apr 17 2019
.UPDATE...
Issued at 942 PM CDT Wed Apr 17 2019
Rain showers were decreasing in intensity and areal coverage
over the past hour across eastern Montana and the western Dakotas.
Isolated thundershowers are possible for another hour or so, with
MU CAPE still at around 250-500 J/kg over western North Dakota.
Farther east, the area of rain showers had shifted moreso into the
eastern third of the state, with only lingering light showers for
the Turtle Mountains and James Valley areas after midnight.
The other concern is that some of the short term high res models
are indicating fog formation - especially for central North
Dakota. Makes sense with the widespread rain and relatively light
winds in central ND, while farther west we have had the
warmer/drier air move in with westerly winds. Thus have added a
mention of areas of fog tonight over most of central ND.
UPDATE Issued at 644 PM CDT Wed Apr 17 2019
Minor changes to keep at least a small chance of of showers and
isolated thunderstorms over the western third of the state through
the evening. A line of showers with isolated thunderstorms were in
western North Dakota, mainly from Williston and Watford City south
to Dickinson/Hettinger areas. Behind or associated with this line of
showers, there could be brief periods of gusty winds over 30 mph.
Otherwise, the area of showers in central North Dakota continued to
move east.
Regarding cloud cover, the north-south clearing/scattering line
between overcast low clouds in central North Dakota and scattered
clouds to the west was approaching the Minot/Bismarck area. Expect
the eastern part of central North Dakota - mainly from the Turtle
Mountains to the James Valley - to remain cloudy tonight.
There may be a chance for fog formation over mainly central North
Dakota - on the western edge of the overcast clouds - especially
since the widespread rains have resulted in moist soil conditions.
Not yet confident of this...depending on whether the light west
winds keep the lower atmosphere mixed. Will monitor trends for later
updates.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 243 PM CDT Wed Apr 17 2019
Latest water vapor imagery shows an upper level shortwave trough
stretching from southeastern into western North Dakota, and
progressing east with time. Deformation zone evident on radar
imagery across north central North Dakota which will allow for
precipitation to continue until 00z Thursday. Across the west,
visible imagery shows subsidence behind the trough with partial
clearing. Glasgow radar shows isolated showers/thunderstorms
within their vicinity now, and this is a sign of the instability
field that will propagate into western North Dakota this afternoon
and evening. As surface heating begins in the west, unstable
conditions develop in the lower levels, with RAP BUFKIT soundings
showing an uncapped environment. Decent low to mid level lapse
rates in place, surface based CAPE up to 400 J/Kg, but deep layer
shear is weak at 20kt. Given a nearly unidirectional wind sounding
with northwest flow aloft, concur with the CAM`s that a weak line
of showers/thunderstorms will initiate in the west and scoot east
this evening. As the indicated, the strongest storms may produce
small hail. This idea still looks good. Expect scattered showers
and isolated thunderstorms through the evening as a 500mb cold
pocket remains overhead. Showers dwindle overnight, however a few
light showers may continue past midnight per latest high
resolution models. This seems reasonable as two more shortwaves
roll through western North Dakota later tonight, then across
central ND Thursday. This sets the stage for a continue chance of
showers and possible thunderstorms Thursday. Severe weather is not
expected. Warm air advection aloft across the west Thursday will
inhibit the threat for convection, with the cold pocket getting
shunted off to the east in the afternoon. Lows tonight will be in
the 30s, with highs in the 50s Thursday afternoon.
.LONG TERM...(Thursday night through Wednesday)
Issued at 243 PM CDT Wed Apr 17 2019
A transitory upper ridge takes control Friday with strong low
level warm air advection. Highs will reach the mid 60s east
central to mid 70s west. Westerly/downsloping winds 15 to 30 mph
will ensue along with minimum relative humidities between 15 and
20 percent especially across southwest and south central North
Dakota. This may lead to potential fire weather concerns and will
continue to monitor. Otherwise, after a warm and dry day Friday,
a cold front will sweep through Friday night into Saturday
morning. Expect a chance of showers and possible thunderstorms
with this cold front. Cooler air will gradually filter in from
west to east Saturday through Sunday. Dry Sunday with highs in the
50s. Monday through Wednesday looks mostly dry as well with highs
in the 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 644 PM CDT Wed Apr 17 2019
Scattered showers and isolated thunderstorms possible at KISN and
KDIK until around 03z. Otherwise VFR for these sites overnight and
Thursday.
Scattered showers and overcast MVFR cigs at KBIS/KMOT should become
VFR by around 03z, then late tonight after 09z MVFR cigs to return
with possible MVFR vsbys in light fog. Becoming VFR after 14z/15z
Thursday.
KJMS to remain overcast through tonight. MVFR with some IFR stratus
around until 03z with scattered rain showers. MVFR/VFR cigs after
03z, with improving conditions after 13z Thursday morning.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...KS
LONG TERM...KS
AVIATION...JV
AREA FORECAST DISCUSSION
National Weather Service Cleveland OH
1011 PM EDT Wed Apr 17 2019
.SYNOPSIS...
A warm front will lift north of the area overnight as low pressure
tracks northeast across the Upper Midwest. The low will continue
east across the Upper Great Lakes on Thursday while another area of
low pressure develops over the Lower Mississippi Valley. This low
will move northeast along the stalled frontal boundary, pulling a
cold front south behind it and bringing unsettled weather through
the first half of the weekend.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
Warm advection and favorable mid/low level jet dynamics have
been enough to generate showers and thunderstorms across NW
Ohio. A few of these thunderstorms were able to produce some
pea size hail. Still uncertainty on how far east these
showers/thunderstorms will make it with dry air in the middle
levels of the atmosphere indicted by the rapid refresh model
suite. So at this point will buy into this scenario and have the
showers/thunderstorms struggle to make much past a Cleveland to
Millersburg line.
Previous Discussion...
A frontal boundary remains stalled across the area extending from
near Findlay to just south of Cleveland. Low pressure over Iowa this
afternoon will continue northeast tonight, pulling a warm front
north of the area with some locations still yet to hit the high
temperature for the day. Mild conditions expected overnight, ranging
from the mid 50s to near 60 degrees with varying degrees of mid and
high level cloud. Regional radars are picking up on a few showers
extending from Lake Michigan to southwest Ohio but have not seen any
reports of this actually reaching the ground given dry air in the
low levels. The HRRR shows some expansion of these showers as
the low level jet develops and moves northeast into Michigan but
model soundings remain dry enough that did not include in the
forecast at this time.
Low pressure will move to northern lower Michigan by morning ahead
of the upper trough deepening over the northern Plains. A good surge
of moisture arrives in northwest Ohio by morning with showers
expanding, mainly west of I-71. A minimal amount of elevated
instability is present and could see a few thunderstorms develop by
morning. Eastward progress of the rain will be slow, not expanding
to northeast Ohio until Thursday night when the cold front arrives.
Areas east of the rain in the warm sector will likely see gusty
winds develop by midday Thursday with a strong wind field
aloft. Mixing depth only expected to reach 2-3K feet but could
tap into gusts of 35-40 knots. Later shifts will need to
evaluate need for a wind advisory for portions of north central
Ohio. Too much expansion of clouds or showers may limit the
winds but expecting some partial clearing in the warm sector
during the afternoon. Temperatures in the east will be well
above normal in the mid 70s. Plenty of room for error in
temperatures again on Thursday night depending on the forward
progress of the front. Current forecast thinking is the front
will be most of the way through the area by late Thursday night
with northerly winds dropping temperatures back into the mid 40s
to mid 50s.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The short term begins Friday with low pressure centered over Ohio.
Will have likely to categorical pops for the area through the day.
Main concern will be the threat of thunder east as unstable air gets
wrapped into the east side of the system during the afternoon. For
now will have a chance of thunder in the morning and chance to
likely thunder for the afternoon. Will continue with categorical
pops for rain most areas Friday night as the low pulls northeast but
another wave develops and moves north across western PA. No big
change Saturday. Sunday another cold front will approach from the
northwest. Will have chance pops for showers for now. Highs in the
50s Friday and Saturday and in the 60s Sunday.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Monday and Tuesday high pressure will be to the north of the lakes
extending south into northern Ohio. Models differ a bit but there
will likely be a front east to west across northern Ohio with
moisture streaming east along the boundary. Will have chance pops
sunday night through Tuesday and again on Wednesday with the region
likely the interface between mild, unstable air from the south and
cool stable air from the north. Will have thunder mentioned during
the days Monday and Tuesday and then everywhere Wednesday. Highs in
the 60s but expect cooler along the lakeshore especially east of
Cleveland.
&&
.AVIATION /00Z Thursday THROUGH Monday/...
Added some thunder to NW Ohio as it developed just before 00Z.
VFR conditions are expected across the region through the
night. A few higher based showers/sprinkles will move eastward
across the area this evening but will likely only produce trace
amounts of rain. These should dissipate as they drift eastward
into slightly drier air at the middle levels of the atmosphere.
The better chance for showers, maybe a thunderstorm, will be
across NW OH around sunrise. These showers/thunderstorms will
slowly drift eastward through the day on Thursday. Most of these
will not reach the OH/PA border until after dark Thursday
evening. MVFR conditions will be possible with the heaviest
showers/thunderstorms.
Winds will be light near the warm front this evening but as it
lifts further northward the southerly winds will reach up to the
lakeshore. Downsloping winds near KERI will become gusty after
04Z. South to southwest winds after sunrise should be in the 15
to 20 knot range with gusts 25 to 35 knots common. The strongest
gusts may approach 40 knots across the west if we see a period
of sunshine.
OUTLOOK...Non-VFR in showers and possible thunderstorms on
Thursday night into Friday. Showers under an upper level low
may keep conditions non-VFR across the region at times on
Saturday and Sunday.
&&
.MARINE...
Low pressure in was Iowa with a warm front east across
northern Ohio. Winds on the lake north of the front were out of the
east at 10 to 20 knots with conditions approaching small craft on
the west end. Guidance suggests winds will not increase through the
evening before veering through southeast to southerly by around
midnight. As winds go south through, expect winds to increase off
the terrain in northwest Pennsylvania bringing winds around 20 to 25
knots to the Erie PA lakeshore region. Will therefor issue a small
craft advisory for that area beginning at 10pm. Will continue the
headlines into Thursday evening before ending. Elsewhere, expect
winds to increase to small craft levels Thursday out of the south
and southwest from 20 to 25 knots as low pressure moves northeast
out of the central lakes and a cold front approaches from the west.
Will not issue for that yet but if guidance remains unchanged, a
headlines may be required. Winds will diminish Thursday night and
turn northwest as the cold front passes. Another low will move
northeast through Ohio friday increasing north flow to 15 to 20
knots and possibly requiring another headline Friday into Saturday.
Winds should remain 15 knots or less Sunday into Monday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 10 PM EDT Thursday for LEZ149.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC/MM
SHORT TERM...TK
LONG TERM...TK
AVIATION...MM
MARINE...TK
Area Forecast Discussion
National Weather Service Dodge City KS
602 PM CDT Wed Apr 17 2019
...UPDATE TO AVIATION...
.SHORT TERM...(This evening through Thursday)
Issued at 154 PM CDT Wed Apr 17 2019
As of 18z Wednesday a surface cold front was moving into south
central Kansas and northwest Oklahoma. RAP and SPC Mesoscale
Analysis page both indicated that the better instability earlier
this afternoon was located near this boundary and ahead of an
upper level trough approaching from the southwest. All the CAMS
earlier this afternoon remained in good agreement and consistent
with previous runs in keeping the best chance for convection this
afternoon and early tonight in this region of instability which
will be located south of a St John to Ashland line. Although a
brief period of large hail and strong winds will be possible
initially...it does look like the storm mode will quickly become
linear and the hazards will shift to heavy rainfall. Thunderstorms
training over the same area early tonight in some locations of
Barber and Comanche counties may cause some minor water issues
with some ponding of water on roadways or poor drainage areas
being possible. Given the latest flash flood guidance am leaning
towards not issuing any type of Flood/Flash Flood Watch but this
is an area that will need to be monitored.
This area of convection will taper off around 06z Thursday as the
upper level trough crosses into central Kansas and our area of
enhanced forcing shifts to the south southeast. As the upper wave
moves east the skies across southwest Kansas will clear and the
lows overnight will bottom out in mainly from the mid 30s to the
mid 40s.
On Thursday another upper level disturbance will cross western
Kansas during the day. Ahead of this upper wave cloudy skies along
with even a few sprinkles/brief light rain showers will be
possible. The area most favorable for any light precipitation
during the day on Thursday will be east of highway 283.
Very windy conditions are also expected to develop during the day
on Thursday across western Kansas as stronger winds aloft mix
down to the surface. Mean mixed layer winds generally are forecast
to range from 30 to 40 knots with wind speeds at the top of the
mixed layer forecast to be between 40 and 50 knots. Gusty north
winds of 25 to 35 mph can be expected which when combined with
afternoon relative humidity values falling back into the 20 to 30
percent range will result elevated fire weather conditions for all
of western Kansas.
The gusty winds will decrease early Thursday evening as an area
of high pressure at the surface builds into western Kansas. At
this time given the clear skies Thursday night and the location of
the center of the surface high early Friday morning it appears
that the temperatures early Friday morning will fall back to
32 degrees, or even a few degrees cooler, in some locations west
of a Ness City to Liberal line. Further east the lows area
expected to be mainly in the the mid 30s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 154 PM CDT Wed Apr 17 2019
Warmer temperatures will return on Friday as an upper level ridge
builds into the Central Rockies and 850mb temperatures start to
warm as westerly downslope flow improves. HIghs in the 70s still
look likely across western Kansas Friday afternoon.
80 degree temperatures will return to southwest Kansas on
Saturday as the warming trend continues. In addition to these warm
temperatures some gusty south winds are also expected to develop
as surface pressures fall along the lee of the Rockies. These
gusty winds combined with afternoon relative humidity values
falling into the 20 to 25 percent range in portions of southwest
Kansas will result in elevated fire weather conditions Saturday
afternoon.
On Sunday our next cold front will move into western Kansas as an
upper level trough crosses the Rockies and moves out into the
Plains. This frontal boundary will be crossing southwest Kansas a
little quicker than what we were looking at yesterday and as a
result it appears that clouds and cooler air returning to western
Kansas during the day will result in highs only in the 60s to low
to mid 70s. This will also be when our next chance for
precipitation will occur also. At this time severe weather is not
expected but most areas of western Kansas will have a chance of
seeing some measurable rainfall, light as this may be.
Next week will begin on the cool side as high pressure at the
surface crosses the Central Plains. Along with cooler, more
seasonal, temperatures there will also be a chance for rain Monday
night and Tuesday as the next upper trough crosses the Western
High Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 600 PM CDT Wed Apr 17 2019
VFR conditions will prevail in the vicinity of all TAF sites through
early Thursday afternoon. Northerly winds 15 to 25kt will subside
somewhat later this evening with the loss of daytime heating. However,
northerly winds are expected to increase 20 to 30kt with gusts up to
35kt late Thursday morning into Thursday afternoon as a secondary
cold front pushes southward across western Kansas.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 41 65 34 70 / 20 0 0 0
GCK 38 63 33 71 / 0 0 0 0
EHA 39 64 38 74 / 20 0 0 0
LBL 42 66 36 73 / 30 0 0 0
HYS 41 63 37 69 / 0 20 0 0
P28 49 67 37 70 / 90 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Burgert
AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
705 PM CDT Wed Apr 17 2019
.AVIATION... /00Z TAFS/
New cell forming south of Dryden would suggest a slight delay in
convective activity around DRT, despite explosive storm growth
expected in the next 1-2 hours. It`s position is well lined up the
the dryline which would take about 2 hours to move that far ESE.
Other cells forming over the Burro mountaintops could spread NE
slightly earlier. Meanwhile CI Probabilities over the capped shower
activity east of I-35 have occasionally spiked over 60 percent, but
the view on satellite and out the window with ragged cloud tops does
not suggest that the cap will break ahead of the organized storm
clusters to the west. Meso model trends and slow onset of
destabilization would suggest that the beginning of the squall lines
rolling into the I-35 terminals will be at or after midnight. Severe
threats will be addressed about an hour or two in advance of the
cells moving into the I-35 Terminals. but only about 30-45 minutes
lead time can be expected at DRT where the storms are more isolated.
Rapid improvements can be expected after 08Z at SAT/SSF and 09Z at
AUS. Gusty winds and fair skies should round out the end of the TAF
periods with models showing the winds not picking up significantly
until around 15Z or later.
&&
.PREV DISCUSSION... /ISSUED 305 PM CDT Wed Apr 17 2019/
SHORT TERM (Tonight through Thursday Night)...
Current surface observations across Texas show the dryline extending
across West Texas (roughly from a Childress to Snyder to Ozona line),
and the cold front pushing south across the Texas Panhandle, having
just made it through Amarillo. It is this cold front that will spur
on the thunderstorms expected tonight into Thursday morning. Current
short-term forecast soundings and the aircraft soundings from AUS and
SAT show the atmosphere still mostly capped across South Central
Texas.
With the capped atmosphere currently storms should hold off through
the rest of the afternoon and into the early evening hours. With the
dryline moving east and the front pushing rapidly south the front
will overtake the dryline and be the lift that South Central Texas
needs for storms. There is plenty of moisture in place with dewpoints
in the upper 60s and 70s. The HRRR and other high resolution
forecast models show storm initiation between 7pm and 9pm across the
Edwards Plateau. When storms do initially form the discrete storms
will have a very good chance of producing large hail to do the
environment with 2500 to 3000 j/kg of instability/CAPE. All of the
models show these discrete storms forming into a line of storms as
they approach the hill country between 10pm and 1am. With 50 knots or
more of bulk shear in place the severe weather threat will continue
as the line approach the I-35 corridor. With the transition into a
linear MCS the threat will also transition from a large hail threat
to a damaging straight-line wind threat within bowing sections of the
line. The line should approach the I-35 corridor between about 11pm
and 2am. Based on all of this a good portion of the Hill Country and
I-35 corridor have been included in the Enhanced Risk from the Storm
Prediction Center, with most of the area in a significant hail hashed
area as well. Basically our entire area is in the slight risk, again
mainly for the large hail and the damaging wind threat. There is a
low risk of tornadoes, but the main risk will be more to the NE
towards the ArkLaTex region.
As the storms push east of I-35 a new threat will be introduced.
While rainfall totals across the area will generally be 1/4 of an
inch to 1 inch, there has been increasing signals that parts of the
area east of I-35 could see isolated totals as high as 2-3 inches.
This could cause some localized minor flooding issues, especially in
areas that have seen decent rains of late. The line of storms will
continues its eastward progression and be east of the area by morning
rush hour on Thursday.
In the wake of the line of storms and cold front a drier airmass
filters in for Thursday. As skies clear strong north and northwest
winds increase. Some portions of the Rio Grande Plains could be close
to wind advisory criteria. In addition, with the lower relative
humidity values dropping down to 20-30 percent elevated to near
critical fire weather conditions are expected across the Rio Grande
Plains and Edwards Plateau. For the rest of the area afternoon highs
will be a few degrees below normal from the mid 70s to low 80s.
Overnight lows Thursday into Friday will also run a few degrees below
normal in the low to mid 50s.
LONG TERM (Friday through Wednesday)...
In the wake of the upper trough that will bring storms tonight into
Thursday morning northwest flow will build in aloft on Friday with
sunny skies continuing. With northerly flow aloft and at the surface
highs Friday will continue to run a few degrees below normal along
the I-35 corridor, with near normal temps along the Rio Grande in the
mid 70s to mid 80s. Southerly flow returns Saturday morning as an
upper level ridge works across Texas. Highs for the weekend will warm
into the 80s area wide, and should flirt with 90 degrees along the
Rio Grande Plains. Clouds return on Monday ahead of the next trough,
with continued seasonal temperatures. All of the long range models
(GFS, Canadian, and ECMWF) show the trough approaching Tuesday, and
moving across the OK/TX Red River Valley Wednesday into Thursday.
With the approaching trough and the moist atmosphere rain chances
begin Monday night and increase through the day Tuesday. Similar to
the system moving through today a cold front will approach Tuesday
night and Wednesday further enhancing rainfall.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 75 54 76 53 / 80 10 0 0 0
Austin Bergstrom Intl Airport 60 75 53 76 51 / 80 10 0 0 0
New Braunfels Muni Airport 59 76 52 78 52 / 80 10 0 0 0
Burnet Muni Airport 59 72 52 75 51 / 80 10 0 0 0
Del Rio Intl Airport 63 82 55 85 58 / 40 0 0 0 0
Georgetown Muni Airport 59 73 52 75 51 / 80 10 0 0 0
Hondo Muni Airport 58 79 52 82 53 / 80 0 0 0 0
San Marcos Muni Airport 59 76 52 77 51 / 80 10 0 0 0
La Grange - Fayette Regional 63 77 53 75 51 / 90 20 0 0 0
San Antonio Intl Airport 60 77 54 80 54 / 80 - 0 0 0
Stinson Muni Airport 60 77 55 80 54 / 70 - 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...Oaks
Short-Term/Long-Term...04
Public Service/Data Collection...BMW
Area Forecast Discussion
National Weather Service Houston/Galveston TX
954 PM CDT Wed Apr 17 2019
.DISCUSSION...
At 9 PM, high pressure was located over the SE US and low
pressure was located over SW OK with a dry line extending south
from the low across the western TX. Some light showers continue
to stream into area from the Gulf but precip has remain widely
scattered and generally light. All that is about to change as a
line of storms approaches the region from the west. Betweem
06-09z, 300 mb winds split as an upper low over West Texas shifts
east and SE TX will lie in a well defined jet couplet. The PW
values surge to 1.90 inches over the western half of SE TX and
there is some weak surface convergence along what looks like a
weak outflow. On water vapor imagery there appears to be two short
waves lined up and the first of these will approach the region
around midnight and help maintain the convection over Central
Texas as it approaches SE TX. Instability parameters are
impressive with LI values near -10, CAPE values 2800 J/Kg and
Helicity around 220. SPC has expanded the Enhanced Risk a bit east
and this seems like the right call based on the instability and
the approaching the short wave.
SPC has also expanded the Slight Risk further east and this now
includes the Houston area. AMDAR soundings still show a strong
capping inversion in place at 700 mb and the million dollar
question is, will the cap hold or will it break. Short term
guidance has been trnding a bit more aggressively with the HRRR
and TT WRF all showing convection approaching Houston around
sunrise as the second short wave approaches the region from the
southwest. Feel the combination of the short wave and strong upper
level diffluence will help to erode the cap and allow a second
area of storms to redevelop over the SW zones and move NE toward
Houston and points northeastward. Instability isn`t quite as
impressive as points to our west but there could still be some strong
storms with gusty winds.
Speaking of winds, the actual front will mot reach the coast until
about 18z. The winds will become N-NW in the wake of the front and
will become strong. A Wind Advisory will likely be required for a
large part of SE TX Thursday afternoon. 43
&&
.PREV DISCUSSION... /ISSUED 704 PM CDT Wed Apr 17 2019/
AVIATION...
A mix of MVFR/IFR ceilings across SE TX this evening, should
continue to lower in height to IFR through the overnight hours and
into tomorrow morning. Scattered light showers are continuing to
develop out ahead of tonight`s cold front. E/SE winds remain gusty
but should slacken ahead of the frontal passage tonight, and
increase in speed out of the W/NW once again tomorrow morning.
Strong to severe storms with gusty winds (primary hazard) and
hail will be possible as the front passes through the region. The
front should arrive at CLL shortly after midnight and reach the
coastal terminals before sunrise. Ceilings will be slow to improve
tomorrow morning, but anticipating VFR criteria by early
afternoon area wide.
Hathaway
PREV DISCUSSION... /ISSUED 340 PM CDT Wed Apr 17 2019/
NEAR TERM [Through Tonight]...
It has been a pretty soupy day today with overcast stratocu and
continued moisture advection over SE Texas. Cloud cover has
limited heating today which means there is not quite as much
instability over the area as there could be and the capping
inversion remains strong. AMDAR sounding from 20Z still shows a
strong cap near 700mb at 12C with very steep lapse rates above
that EML inversion. Surface Theta-E axis continues to run through
central Texas and seeing some showers form on the eastern edge of
this axis near the Brazos Valley. Right now there does not appear
to be enough large scale lift to help erode the cap or a jet
streak for divergence. If anything, water vapor imagery shows a
jet streak departing the area so look for neutral/subsident
vertical motion to continue the next few hours. The upper level
low has moved into New Mexico with one part of the polar jet
coming across the Big Bend and West Texas. Southern part of this
jet should spread over south Texas overnight and into parts of SE
Texas by 12Z Thursday. LLJ will be strong but veer around to the
SW or WSW ahead of the front and strong jet forcing. There is
still a very good chance of showers and thunderstorms mainly 06Z
to 12Z Thursday. The WRF/HRRR continue to show a squall line
moving into the area around 06-09Z with it becoming weaker 09-12Z
Thursday. This is just in time for Houston morning commute from
4AM to 8AM Thursday. We still think SPC outlook is on track
especially concerning the capping limiting the severe threat
closer to Houston and the coast. There could be some locally
heavy rainfall as well but that may depend upon available
instability and lift with the higher moisture. Again capping will
be the main limiting factor. Upper level lift may just be enough
out of phase to keep the cap in place. These are finer details
that need to be monitored overnight as convection develops and
adjust based on further analysis/guidance.
Overpeck
SHORT TERM [Thursday Through Friday Night]...
Deep upper level trough should develop east of the area over the
Mississippi River Valley by Friday morning. Line of storms should
be exiting the region Thursday morning as the initial trough axis
moves past the area into Louisiana. A cold front at the surface
should usher in cooler/drier air into the region for the holiday
weekend. We will need to keep an eye on fire weather conditions as
winds will be pretty gusty from the north with after RH values
getting down around 30-35 percent.
Overpeck
LONG TERM [Saturday Through Wednesday]...
Upper level ridging should continue over the area for the weekend
with one short wave trough moving across the southern Plains
Sunday as another trough develops over the Rockies Sunday night.
GFS/ECMWF/Canadian all have fairly different solutions for the
upper level pattern for early next week from Monday into
Wednesday. GFS has the trough splitting with still some troughing
back to the west while the ECMWF/Canadian have a slower evolution
of the trough. At this point lean more on a slower moving trough
which the models in some shape/form somewhat agree with on
Wednesday next week. However the surface details are all very
different and rather not focus on those details since we are
looking at the day 6-8 part of the forecast. Forecast will show
rain chances slowly ramping up Monday through Wednesday.
Overpeck
MARINE...
Moderate to strong onshore winds and building seas are expected
to develop this afternoon and tonight as the gradient tightens
ahead of the incoming storm system. Showers and thunderstorms
will be pushing west to east across the waters tomorrow morning
with a westerly wind shift. The storm system`s cold front is
still expected to push through the area in the afternoon with
northwest winds increasing in its wake. There could be a period
of lower winds and seas (below caution/advisory levels) just
ahead of the storms and again just behind the storms, but winds
and seas should come back up to those levels after the front
moves through the area. Could see some minor overwash at Highway
87/124 on the Bolivar Peninsula tonight around high tide time
(~4am), and then we`ll need to keep an eye on possible low water
conditions late Thursday night and on into Friday morning at low
tide time across northern bay locations. Winds will weaken late
Friday an on into Friday night as high pressure builds into the
area. Onshore winds come back to the area on Saturday and persist
for the remainder of the weekend and on into at least the first
half of next week. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 80 63 76 52 74 / 40 100 40 0 0
Houston (IAH) 78 66 80 54 75 / 40 90 80 0 0
Galveston (GLS) 76 70 78 60 74 / 40 60 80 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for
the following zones: Galveston Bay...Matagorda Bay.
Small Craft Advisory until 6 AM CDT Thursday for the following
zones: Coastal waters from Freeport to Matagorda Ship
Channel TX out 20 NM...Coastal waters from High Island to
Freeport TX out 20 NM...Waters from Freeport to Matagorda
Ship Channel TX from 20 to 60 NM...Waters from High Island
to Freeport TX from 20 to 60 NM.
&&
$$
Discussion...43
Area Forecast Discussion
National Weather Service Lincoln IL
910 PM CDT Wed Apr 17 2019
.UPDATE...
Issued at 908 PM CDT Wed Apr 17 2019
The line of storms is progressing along at a timing that is close
to the CAMs recent projections. Instability remains the primary
focus for storm intensity, with shear generally on the marginal
side. DCAPE values of 600-800 J/kg appear sufficient to support
some pockets of damaging winds from the stronger updrafts. A few
hail cores could reach up to nickle size, but strong winds should
be the primary severe threat overnight. Instability does weaken
with time overnight, so the initial wave of storms between
midnight and 3 am will have the better chances of producing the
stronger winds and possibly severe hail. Surface based instability
will be difficult to maintain overnight, with areas of dewpoints
in the 60s have the best chance at that. The I-55 corridor
currently has some dewpoints in the low 60s, so will monitor that
area for higher threat of severe winds.
The severe threat will continue east of I-55 between 3 am and 6
am, with pockets of strong winds possible. But overall severe
potential should diminish the later in the night the line
progresses toward Indiana.
Updates this evening were to delay the PoPs and storms a couple of
hours, to late evening start times. Otherwise, the remainder of
the night looks on track. Strong southwest winds will continue
ahead of the cold front, then weaken as the front nears and
passes. Gusty NW winds will lag the FROPA by a few hours, but
gusts look to return to 15 to 25 mph again early Thursday morning
west of I-55.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 305 PM CDT Wed Apr 17 2019
Shortwave over IA and surface low to track east overnight,
dragging frontal zone eastward, reaching northwest IL by 06z. Good
moisture advection moving northward over MO into east IA and
northwest IL/southern WI. Hi Res short range models develop
convection in frontal zone over MO in strong southward inflow into
convergence zone. Convection then trails off to east into IL over
night. Time of the day may be a hindrance on severity of
convection, as CAPEs should decrease overnight, but latest HRRR
models still move significant linear convection across area.
Frontal zone pcpn to continue to sag east til early morning hours.
Some heavy rain possible with some storms.
Lingering convection through Thursday, mainly in the east. Most of
this will be post frontal and so the severe nature of storms will
be limited and scattered. Heavy rain biggest threat.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 305 PM CDT Wed Apr 17 2019
For friday, still have some wrap around showers on back side of
the upper system that is progged to be over mid Atlantic states.
Dry surface ridging over area through Saturday and into start of
Sunday.
For Sunday though, next frontal zone progged to move into from the
northwest, reaching central IL by evening. Overrunning pcpn to
develop due to front in the plains, and models a little different
on eastward development. Both EUR and GFS do agree on pcpn in
region on Sunday night, but differ in the position of the front,
with the EUR farther to the south as the that model has Great
Lakes upper trough stronger and the upper wave in the southwest
weaker.
Be Tuesday to Wednesday, EUR model has front further south of
central IL. WPC frontal graphics went more with EUR trends. As
result, spotty areas of low pops off and on into Wed.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 704 PM CDT Wed Apr 17 2019
A line of storms is expected to push across the TAF sites
from late evening to early morning, as a cold front advances from
Iowa to Indiana overnight into Thursday morning. MVFR clouds are
likely to develop as the storms arrive, with IFR clouds and
visibility possible for shorter periods of time as thunderstorms
pass over any TAF site. Timing looks to be from west to east
starting at PIA and SPI around 04-05z, then reaching CMI to DEC
between 08z-09z. Rain and showers will likely linger on Thursday
for the eastern terminals, as the frontal boundary slows down in
E-SE Illinois. A few morning thunderstorms will also be possible
for CMI and DEC mainly.
Winds look to remain gusty from the SW this evening, at 15g30kt
early, diminishing to 10g20KT by mid evening, then around 5-10kt
as the cold front approaches/passes each TAF site. Winds will
shift to westerly later tonight, then become NW and increase to
12g22KT by 17z-19z in most areas.
Ceilings look to improve from low MVFR around sunrise, to VFR by
mid to late afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...Goetsch
LONG TERM...Goetsch
AVIATION...Shimon
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
924 PM CDT Wed Apr 17 2019
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Tightening pressure gradient over central sections has resulted in
some gusty winds this evening. This will be the trend overnight
with a gradual increase in speeds toward morning. The latest HRRR
data continues to show the brunt of the convection coming into the
area after 15Z. Remainder of forecast package still looks good. No
other significant changes expected./GG/
Prior discussion below:
Through tomorrow night...
Shortwave ridging over the region today will lift off to the
northeast as a strong shortwave trough ejects out of the Desert
Southwest and into the Southern Plains before lifting through the
Lower Mississippi River Valley tomorrow. Capping will keep rain
chances confined to an isolated shower or two over the far northwest
Delta today before rain chances quickly ramp up tomorrow morning.
Upstream showers and thunderstorms will progress across the ArkLaTex
overnight with decaying convection progged to stall over portions of
the Delta during the early morning hours. A few of these early
storms could be severe with damaging winds, hail up to quarter size,
and a tornado or two cannot be ruled out.
Lee side cyclogenesis will occur over the High Plains with the main
low lifting northeast into the upper Midwest by tomorrow morning
with an attendant cold front draped through the Mississippi River
Valley. A perturbation propagating along the frontal boundary over
east Texas will help induce a second area of cyclogenesis beneath
favorable upper jet dynamics with a deepening low (~995mb) lifting
through southern Arkansas into far northern Mississippi through the
day tomorrow. Resulting low-level mass response will help enhance
the wind fields with flow strengthening as it becomes increasingly
backed yielding veering wind profiles with height and strengthening
vertical wind shear, especially in the 0-1km layer. This will be
occuring within a warm sector characteristic of upper 60s dewpoints
and 1000-1500 J/kg of MLCAPE which will be supportive of organized
severe convection. This morning`s hi-res CAM guidance is in fairly
good agreement on possible convective evolution depicting an area of
warm air advection convection, including the potential for semi-
discrete supercells, lifting northeast into southern Mississippi
ahead of a strongly forced and intense QLCS. As strong surface
pressure falls and mid-level height falls overspread the area
eventual upscale growth into a solid line of storms is expected. In
terms of hazards, tornadoes, of which a strong tornado cannot be
ruled out, damaging straight line winds of 70-80mph, and hail up to
quarter size are all expected. The ongoing enhanced risk area will
be maintained in the HWO/graphics.
In addition, flash flooding will be a concern with anomalous
moisture in place as PWATs surge to near 2". Training convection
with high rainfall rates will result in 2-4" of rain with locally
higher amounts over a short amount of time which will lead to flash
flooding issues. A flash flood watch has been posted for all areas
except the far southwest corner of the CWA and the HWO/graphics have
been updated to include an elevated threat area. There are two main
areas where swaths of higher QPF could be realized. The first will
be over the Delta where early morning training convection will be
possible, and the second area is roughly from Brookhaven to just
north of Meridian where warm air advection storms could train ahead
of the main line.
Storms will exit the area into Alabama by the early evening hours,
although a few showers could linger through the overnight.
Temperatures tonight will be mild as mixing and moisture advection
beneath increasing cloud cover preclude greater cooling potential.
Locations across eastern Mississippi ahead of the line of storms
could warm close to 80 tomorrow with other locations remaining in
the low to mid 70s. /TW/
Friday through Tuesday night...
The main system from Thursday will exit the region around Friday
morning but a short wave trough with a positive tilt axis will
allow for some rain wrap and moisture bringing in some lingering
cloud cover and showers for the rest of the day. By Saturday all
precip will have cleared the area. Some slight northwesterly flow
will persist bringing in cooler temperatures for the morning but
will shortly get replaced as a upper ridge builds out west Sunday.
This will bring increasing heights and with the influence of
southerly flow, highs will climb to near 80 degrees F.
For next week, there is some discrepancies within the models as
the GFS shows a more profound ridge and the Euro and Canadian
favoring a weak trough with a possible stalling front. With the
chance of this front possibly hanging over to the north west
which will increase moisture, a low chance of PoPs were added to
account for that. With models still in disagreement for the later
work week only minor changes were made to the extended forecast.
/JE/
&&
.AVIATION...
00Z TAF discussion: VFR ceilings will increase and lower tonight
eventually becoming MVFR prior to sunrise. Isolated to scattered
showers and thunderstorms will begin developing from the west
after sunrise. While ceilings will mostly become VFR by afternoon,
they will quickly be lowered to MVFR/IFR when showers and
thunderstorms move through. Winds will increase to 10 to 15 knots
from the south with gusts around 25 knots during the
afternoon./GG/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 62 76 51 62 / 5 99 54 37
Meridian 62 79 52 62 / 10 99 97 38
Vicksburg 65 75 52 65 / 7 99 47 31
Hattiesburg 63 80 53 64 / 10 99 97 34
Natchez 65 77 51 65 / 6 100 47 32
Greenville 66 72 50 63 / 17 99 51 23
Greenwood 64 74 50 61 / 4 99 62 35
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Flash Flood Watch from 7 AM CDT Thursday through Thursday
evening for MSZ018-019-025>052-054>058-062>066-072>074.
LA...Flash Flood Watch from 7 AM CDT Thursday through Thursday
evening for LAZ007>009-015-016.
AR...Flash Flood Watch from 7 AM CDT Thursday through Thursday
evening for ARZ074-075.
&&
$$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
939 PM EDT Wed Apr 17 2019
.SYNOPSIS...
High pressure over the western Atlantic will continue to
influence the weather through Thursday. A strong frontal system
will impact the area Friday into Saturday. High pressure will
build into the region early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 930 PM Wednesday...No adjustments were made to the
previous forecast. Despite a slow temp fall due to high clouds
and a slight southerly breeze, stuck with our lows in the middle
to upper 50s tonight. Hourly temps now match up well with the
RAP and HRRR which still shows lows tonight around what we
already have.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 345 PM Wednesday...High pressure offshore begins to slide
eastward as the frontal system continues to advance toward the
region. Dry weather continues as the mid levels remain very dry
but will see increasing high clouds through the day with sct
cumulus during the afternoon as southerly flow brings increasing
low level moisture. It will be another warm day with highs in
the low to mid 80s inland to mid to upper 70s along the coast.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 325 PM Wed...Dry but increasingly cloudy conditions give way
to a very strong storm system passing inland Friday, bringing a cold
front and a myriad of associated hazards across the area later
Friday into Sunday morning. Dry weather is forecast to prevail into
mid-week.
Thursday night through Saturday...An exceptionally high amplitude
upper trough (500 mb geopotential height > 3 standard deviations
below normal based on NAEFS) digging across the eastern US will
develop a cutoff/stacked low over the Mississippi and Tennessee
Valleys Thursday night into Friday. This low, in combination with
the persistent high offshore, will help develop deep layer southerly
flow/moisture advection locally. Cloud cover will increase
overnight, with eastern NC experiencing mostly cloudy skies Friday.
The increased cloud cover, combined with the development of isolated
to widely scattered showers forecast early Friday in a conditionally
unstable airmass, will help limit instability and thus severe
potential during the day.
Severe risk increases Friday evening as the stacked low moves over
the southern Appalachians, with very strong winds on its east side
throughout the column. Guidance continues to show a LLJ with winds
of 50-60 kt at 925 mb ahead of a cold front that will cross the area
Friday night into Saturday morning. Gusty to strong winds will
arrive with the jet, especially for coastal areas, and a Wind
Advisory appears likely in future packages. A High Wind Warning is
possible for the Outer Banks. There is a risk of minor coastal
flooding for the northern Outer Banks mainly north of Oregon Inlet.
Additionally, the primary band of prefrontal moisture convergence
will cross the area Friday night and despite continued limited
instability (about 1000 J/kg per ensemble guidance), showers and
thunderstorms will bring the potential for damaging wind gusts as
they readily mix the very strong LLJ winds to the surface. An
isolated tornado threat and heavy downpours leading to localized
minor flooding are also possible with the strongest convective cells.
The cold front will be near the coast by sunrise Saturday, and
push off the coast through the day. True CAA will not occur
immediately behind the cold front as the stacked low lifting
across the Great Lakes will remain in control, bringing atypical
post-frontal southwesterly flow. However, subsidence aloft will
bring settled conditions despite the lack of significant low
level airmass change.
Sunday through Tuesday...Subtropical high pressure is expected to
ridge into the area early next week, bringing rain-free conditions
and near to above normal temperatures. A backdoor cold front may
make an approach towards our region during the period, but despite
model timing differences this feature currently does not look like
it will bring any sensible weather impacts.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term /through Thursday/...
As of 730 PM Wednesday...High confidence that VFR conditions
will dominate through the TAF period as dry high pressure
continues over the area with light winds and high Cirrus clouds.
Could see patchy light ground fog briefly early Wed morning
where winds partially decouple but it is not expected to have
significant impacts at the TAF sites. Pressure gradients begin
to tighten Thursday with the approach of a frontal system and
could see peak gusts up to around 20 kt during the afternoon but
gusty conditions will begin by mid morning as soon as we get a
bit of mixing.
Long Term /Thursday night through Monday/...
As of 325 PM Wed...VFR conditions initially Thursday night will
deteriorate beginning early Friday as a frontal system
approaches from the west. This front will bring the potential
for widespread sub-VFR Friday into Friday night with showers and
thunderstorms impacting the terminals at times. Additionally,
very gusty winds will occur ahead of the front, especially near
storms, as a strong LLJ moves overhead late Friday. Low level
wind shear is also expected during this time. More settled (VFR)
conditions will gradually ensue again on Saturday and dominate
through early next week.
&&
.MARINE...
Short Term /through Tonight/...
As of 930 PM Wednesday...Quiet conditions on the waters this
evening with southwest winds 10 to 15 knots and seas 2 to 3
feet. High pressure to our east now will continue to move
eastward Thursday as a strong frontal system approaches from the
west bringing tightening pressure gradients. Winds will become
S/SW around 5-15 kt throughout this evening and continue
overnight, then S winds increase to 15-20 kt on Thursday. Seas
will generally be around 2-3 ft tonight into Thursday morning,
then build to 3-5 ft by late afternoon.
Long Term /Thursday night through Monday/...
As of 325 PM Wed... Conditions deteriorate Thursday night as a
very powerful low pressure system begins to impact the
southeastern US. Strong winds ahead of an approaching cold front
will bring a high confidence gale event beginning early Friday
morning and continuing through Friday night. Storm Force winds
are possible mainly across the coastal waters from Oregon Inlet
to Cape Lookout Friday night. Accordingly, seas will rise
rapidly beginning late Thursday night, with seas that are very
dangerous for all size vessels, as high as 18 to 20 ft within 20
NM of Hatteras Island, occurring Friday night. Overall,
extremely dangerous marine conditions are on tap Friday and
Friday night. The cold front will cross the waters Saturday
morning, and conditions will begin to improve through the day
Saturday, though SCA winds and seas will likely linger into
Saturday night and possibly Sunday.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MHX
NEAR TERM...EH/SK
SHORT TERM...SK
LONG TERM...MS
AVIATION...EH/SK/MS
MARINE...EH/SK/MS
Area Forecast Discussion
National Weather Service Marquette MI
627 PM EDT Wed Apr 17 2019
.SHORT TERM...(This evening through Thursday)
Issued at 415 PM EDT WED APR 17 2019
WV imagery and RAP analysis indicated a mid/upper level trough the
northern and central Plains with a well defined shortwave into
southwest WI. Radars indicated moderate to heavy rain from eastern
MN through northern MN with embedded tsra on the srn portion of the
rain area. At the surface, low pressure was located over nrn IA with
a warm front through far nrn IL.
Radar/satellite trends suggest that the heavier rain associated with
the comma head portion of the shrtwv will move through mainly
western Upper Michigan. However, stronger moisture transport and low
isentropic lift will also support heavier rain through the southeast
half of the cwa especially as a trailing shrtwv over IA moves toward
the area by late evening. In addition, forecast MUCAPE values at or
above 500 J/Kg suggest tsra will also be more likely over the south.
The combination of rainfall to around an inch and additional
snowmelt could result in minor flooding on small streams and
significant ponding water.
Increasing CAA behind the low will draw enough colder air into the
west for a mix or change to snow toward 06z, per NAM wet-bulb zero
height forecasts. Snowfall amounts of an inch or two may be possible
overnight.
Thursday, moist northerly upslope flow will support continued
lake/terrain enhanced rain/snow over the west half in the morning
that will gradually taper during the afternoon. Any additional snow
amounts will be less than an inch. Otherwise, colder conditions
return with blustery north winds and highs in the lower 40s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 427 PM EDT WED APR 17 2019
During the long term, a lower amplitude, split flow pattern will
become the rule across the CONUS/southern Canada with the northern
stream dominant. After the mdt to potentially hvy rainfall tonight
and then the snowmelt that will be occurring into and thru next
week, this pattern will fortunately be a drier one for Upper MI.
Even so, will likely see some river flooding develop over time.
There will be 2 northern stream shortwaves affecting Upper MI during
the long term, one Sun and the other midweek. With little moisture
avbl with the first wave, rain chc will be limited as the wave
passes on Sun. The next shortwave will bring a chc of rain at some
point in the midweek period. As for temps, after a chilly Thu, sunny
days under a dry air mass Fri/Sat will lead to significant warming
with highs on Sat well above normal over the w. Passing cold front
late Sat night and Sun will bring some cooling, most notably near
Lake Superior. Then, temps Mon thru Wed will be close to normal, but
probably leaning above normal in areas not affected by lake
moderation.
Beginning Thu night/Fri, if there is any lingering -ra/-dz late Thu
aftn, it will end from w to e Thu evening, followed by clearing
skies into Fri. Deep, dry air mass on Fri will support sunny skies
or clearing to sunny skies where any clouds still linger to start
the day. Temps will respond by rebounding into the 50s, except near
Lake Superior. Stronger gradient flow across Lake Superior into the
eastern fcst area will keep temps lower in that area, and no higher
than around 40F close to the lake. Given the very dry air avbl for
mix down as the boundary layer builds during the day, incorporated
some of the drying based on mixing heights to lower dwpts during the
aftn.
Clear/quiet night Fri night under passing sfc high pres ridge will
be followed by a warm day on Sat, especially so over western Upper
MI under southerly flow. With sfc high pres ridging back to eastern
Lake Superior and northern Lake MI, it will be cooler over the e,
particularly along the Lakes. Will turn cooler thru the day over the
Keweenaw and along the lake over the n central as winds back under
developing lake breeze wind component. Over the w, a continued dry
air mass and 850mb temps around 5C will support temps rising well
into the 60s. Some of the traditional warm spots may touch 70F.
Given the still very dry air avbl for mix down as the boundary layer
builds during the day, once again incorporated some of the drying
based on mixing heights to lower dwpts during the aftn.
Shortwave will shift e to northern Ontario by Sun morning. There is
quite a spread among the models in timing the associated cold front
across Upper MI. The GFS has the front exiting the fcst area by 12z
Sun, the ECMWF during the aftn and the CMC not until Mon morning.
ECMWF has shown good consistency on the timing and fcst will lean in
that direction. With limited moisture and modest forcing, not
expecting much for shra activity in the vcnty of the front as it
passes. Clearing will follow. While it will be chilly or become so
near Lake Superior where w to nw winds are onshore Sun, it will
still be warm inland. Over the s central, downsloping postfrontal w
to nw winds will help push temps back above 60F.
High pres will build se across northern Ontario and the northern
Great Lakes on Mon, providing a mostly sunny, but cooler day. Temps
will reach the 50s well inland from Lake Superior. Along the lake,
temps will be no higher than the upper 30s/lwr 40s.
Next shortwave will arrive midweek, bringing a chc of shra. GFS is
an outlier, showing more of a southern stream link up which results
in a much wetter period. However, there is not much support for such
a solution from the GFS and CMC ensembles.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 627 PM EDT WED APR 17 2019
Expect rain to continue as a low pressure system moves to southeast
Minnesota and an associated warm front lifts across Wisconsin and
lower Michigan. Plan on conditions deteriorating to IFR or lower in
periods of rain and fog at all sites this evening as the low
pressure system lifts tracks toward northern lower Michigan. Enough
cold air will occur in the low levels for the rain to mix with or
even change to snow at KCMX by late this evening. Northerly upslope
flow will maintain IFR/LIFR conditions for much of Thursday
at all sites.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 415 PM EDT WED APR 17 2019
As low pressure approaches the region, NE winds will increase to 25
to 30 knots tonight and then become N Thursday morning and diminish
to around 20 knots Thursday afternoon and Thursday night. Expect
diminishing winds Friday with winds below 20 knots through the
weekend.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Rolfson
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Springfield MO
657 PM CDT Wed Apr 17 2019
...Mesoscale Discussion and Update to Aviation...
.MESOSCALE DISCUSSION...
Issued at 629 PM CDT Wed Apr 17 2019
A few storms have fired early this evening along a boundary
extending northeast from near Eureka to Garnett, KS and then into
the eastern Kansas City metro. This boundary has been slowly
lifting north over the last hour. Farther southwest along this
boundary, thunderstorm activity is more numerous in northwest OK.
Meanwhile a synoptic cold front extends from just south of St.
Joseph, MO to near Topeka to Hutchison, KS. Storms have started to
fire along this front in northwestern Missouri and extreme
northeastern Kansas. Activity along this front should backbuild to
the southwest this evening rather quickly, especially as it
reaches the other boundary.
Meanwhile, the 00Z KSGF RAOB indicates that a fairly strong
capping inversion remains in place across the Ozarks. We therefore
think that thunderstorm potential will come in two phases from
later this evening into the overnight period:
1) Widely scattered activity developing in the warm sector across
northern Arkansas and southern Missouri later this evening as a
low level jet stream strengthens and noses into the region.
Thunderstorms would tend to be elevated in nature, but could pose
a hail threat.
2) Scattered to numerous storms along the cold front starting
around 9-10 PM over extreme southeastern Kansas and west-central
Missouri. These storms will then sag southeast with time along
that front overnight.
Hail up to the size of golf balls will be possible with any
discrete storms. Otherwise, severe hail size potential will
generally be in the quarter to half dollar range.
There will be a damaging wind threat with the line of storms. This
will especially be true with any bow echoes that move out of
Kansas and Oklahoma. It should be noted that CAMs and several runs
of the HRRR have indicated this potential, especially across
southeastern Kansas and southwestern Missouri.
The tornado threat remains limited and will be confined to any
bow echoes which surge towards the northeast. We will have to
pay particular attention to any bow echoes tracking northeast
along any quasi-stationary outflow boundaries that may be
present.
The threat for flooding looks very low at this point given that
this cold front and expected line of storms should remain fairly
progressive.
&&
.SYNOPSIS...
Issued at 225 PM CDT Wed Apr 17 2019
Visible satellite and observations continue to show a stratus layer
across the area and special 18z SGF sounding continues to show EML
above the stratus deck. Cold front stretched from western Iowa
into northeast KS and into the TX panhandle. Regional radar
was showing most of the convection at this point associated with
the low in Iowa and Minnesota, although some storms have started
to now form in the Texas panhandle. Most of the region still had a
thermal cap in place and should prevent convection from developing
until very late afternoon or early evening along the cold front.
The storms will be the main focus in the short term.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 225 PM CDT Wed Apr 17 2019
As mentioned in the synopsis, 18z soundings from SGF into the
southern plains showed a thermal cap in place which will likely
hold until this evening when convection should start to develop
along the front. The front will gradually work southeast into the
area this evening with strong to severe storms. By this time, we
are expecting most of the convection to become linear with the
frontal boundary with the main risk being damaging straight line
winds and some hail. If any bowing line segments can develop
towards the northeast, there could be a chance for a spin-up
tornado within the line segment. Most of the area will have a time
frame from mid-evening into the overnight hours for the severe
potential. Don`t see much of a flooding risk, given the green-up
taking place and the progressive nature of the front, although
heavy rain is expected with the convection.
The convection will linger into Thursday morning over the eastern
Ozarks, but should come to an end during the afternoon hours. If
there is enough instability, then some strong to severe storms
will remain possible.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 225 PM CDT Wed Apr 17 2019
Cooler temperatures will linger into Friday as the back side of
the upper low continues to push through. Highs will be from the
upper 50s to mid 60s.
We should begin to warm back up over the weekend, into the 70s as
an upper ridge builds in behind the upper trough. Models do show
some differences with the strength and timing of the next energy
on Sunday, but both have some showers/thunderstorms possible by
late in the day into Sunday night.
It looks to remain unsettled through the remainder of the long
term period with a slow moving upper trough and low closing off
over the region by the middle to later part of next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 629 PM CDT Wed Apr 17 2019
Scattered to numerous thunderstorms are expected overnight along
an advancing cold front. MVFR conditions will become likely
overnight with gusty and erratic winds also expected around
storms.
There is then some potential for IFR early Thursday morning behind
the departing thunderstorms. Otherwise, MVFR is expected Thursday
morning with northwest winds increasing behind the front.
VFR should then return Thursday afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...Schaumann
SYNOPSIS...Lindenberg
SHORT TERM...Lindenberg
LONG TERM...Lindenberg
AVIATION...Schaumann
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Thursday)
Issued at 317 PM CDT Wed Apr 17 2019
Focus through late tonight remains on thunderstorms chances and
their impacts.
Central Plains remains flanked by main two upper level systems to
the north and south. Surface cold front is somewhat ill-defined
with an apparent boundary from near Marysville to Abilene, and
another from Medicine Lodge to near Lubbock TX at 19Z. Isolated
convection has persisted to the north and northeast along the
northern boundary early this afternoon with visible satellite
trends also not supporting rapid destabilization despite RAP
analysis suggesting little convective inhibition. Low clouds ahead
of the front remain rather persistent and are keeping strong
heating and mixing in check.
Most guidance is similar in scattered to numerous convective cells
developing around 0Z along a consolidated front in southern
portions of the local area, however some rapid-updating solutions
keep some separation to the aforementioned boundaries into the
early evening. The persistent cloud suggests inhibition remains
considerable and expect the stronger convergence that develops
late today will be needed for the most convection to occur, but
will keep some small chances along the northern boundary early on.
Deep shear remains fairly strong though vectors are oriented
along the boundary and suggest somewhat unorganized and varied
storm motions and types and should keep concerns limited to hail
and wind. Synoptic boundary is rather slow moving and there will
be some potential for training though outflow from any segments
moving off the line could push the effective front south to keep
persistent heavy rains to the southeast. Southern upper trough
should reach central portions of Oklahoma well before dawn and
usher the front well southeast by late tonight.
Deep north-northwest flow develops Thursday as a weaker wave
rotates around the consolidating upper trough. Cool temps aloft
and meager low level moisture may allow for isolated to scattered
showers to form with diurnal mixing in much of the area Thursday
afternoon. Pacific nature to the airmass brings highs back into
the lower to middle 60s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 317 PM CDT Wed Apr 17 2019
Winds Thursday evening back off as skies clear but expect temps to
remain above any frost concern. Northerly flow continues into
Friday night as the upper trough deepens to the southeast and a
northerly low-level wind component to the winds across the
western Gulf of Mexico through early Saturday. Multiple upper
troughs work their way east into the western and central Plains
Sunday into at least Tuesday with much to be determined on their
placement and timing. The aforementioned Gulf wind character
should keep instability and moisture muted but at least diurnal
thunderstorms will be possible. There is general agreement for
upper ridging to return around Wednesday for lesser precipitation
chances. Temperatures should remain relatively close to normal in
this regime.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 630 PM CDT Wed Apr 17 2019
Maintained a VFR forecast for the terminals through the night.
There may still be a window of opportunity for showers or perhaps
an elevated thunderstorm over the next several hours generally
through 06Z. However, as the cold front continues to advance south
this opportunity may wane quicker. Expect winds to increase
overnight into the morning from the northwest. May need to
increase the gusts in subsequent forecasts.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...65
LONG TERM...65
AVIATION...Drake