Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/15/21
Area Forecast Discussion
National Weather Service La Crosse WI
1041 PM CDT Fri May 14 2021
.SHORT TERM...(This evening through Saturday)
Issued at 252 PM CDT Fri May 14 2021
A weak 500mb shortwave was generating a loosely organized, north-
south oriented band of very light showers/sprinkles from eastern MN
down through central IA early this afternoon. Very dry air in the
low levels per regional observed soundings and RAP guidance has been
limiting how much rain can make it to the surface, but indeed some
stations just upstream have been reporting light rain at times -
surprising, considering the nearly 30 degree dewpoint depression in
place. This large T-Td spread has also led to very low RH in the
teens to 20s, but southerly winds have been in check for the most
part from a fire weather standpoint with only occasional gusts
around 20 mph. The deep, dry mixing and somewhat slower cloud
progression has allowed temperatures to climb a bit higher than
anticipated, especially east of the Mississippi River where 1 PM
readings were in the mid 60s to lower 70s.
Any rain that manifests west of the Mississippi this afternoon
should be primarily just sprinkles. Forecast soundings start to
moisten up in the low levels this evening as mixing diminishes,
which will lend itself to a greater chance of steadier rainfall
getting down to the surface tonight. Not only that, but a
reinforcing shortwave will drop through the region tonight to offer
slightly better forcing. That said, we`re not looking at any
substantial rainfall potential...those that get any rain will be
lucky if they receive 0.1 inch. Nudged low temps upward a bit given
widespread cloud cover and weak warm advection tonight. Lows will
range from 40s to around 50.
The shortwave will be overhead around daybreak Saturday, slowly
progressing eastward through the day and taking better precip
chances with it. As cloud cover thins a bit from the west, will have
to watch for a small amount of instability building ahead of yet
another weak wave of energy progged to drop into the area in the
afternoon. This feature will be accompanied by a wind shift near the
surface that should provide enough low-level convergence and
instability to generate a broken line of showers and perhaps a few
thunderstorms. Deep layer shear overhead remains weak through late
afternoon, so not expecting strong storms. Highs Saturday in the 60s
to near 70.
.LONG TERM...(Saturday night through Friday)
Issued at 252 PM CDT Fri May 14 2021
Rain chances diminish with loss of heating and shortwave energy
Saturday evening, with much of Sunday looking dry. Another
shortwave passes through Sunday evening into Monday morning, but a
second area of shortwave energy moving south of the area looks to
focus the better moisture transport and instability south of the
area as well. However, portions of northeast Iowa into southwest
Wisconsin may still get in on some shower activity. The upper-
level pattern looks somewhat messy for early next week, with
developing eastern CONUS ridging but some energy working northward
toward the area as the ridge develops. This energy is enough for
the blend to give small PoPs Tuesday, but given what appears to be
a weak lobe of surface ridging with drier east-northeast flow
into the area, it wouldn`t be surprising if it ends up being on
the drier side for most. Highs look to be in the 70s to possibly
even 80s. The NBM deterministic values continue to be lower than
much of its percentile guidance would suggest, with NBM 50th
percentile a good 3-6 degrees warmer and suggesting widespread 80s
to start the week. If things do end up dry with mixing/some
sunshine, 80s appear very plausible.
Increasing southerly flow will bring in mild and increasingly moist
air for Wednesday into the latter half of the week, with the return
of shower and thunderstorm chances as a stronger shot of shortwave
energy approaches in southwest flow aloft on the back side of the
eastern ridge.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1041 PM CDT Fri May 14 2021
Weak disturbance and subtle low level moisture return still
triggering patchy showers overnight but ceilings remain in VFR range
for most part, especially with such dry air to fight. This might
gradually worsen overnight as a few more MVFR ceilings develop, but
confidence not the highest given recent drier trends.
Other thing to watch will be approach of stronger short wave trough
in northwest flow Saturday afternoon. This could trigger some
stronger convection with hints of instability and weak shear
present. Details will have to be refined as threat draws closer but
could see some intermittent MVFR conditions with associated
thunderstorms before wave passes going into Saturday evening.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Kurz
LONG TERM...Lee
AVIATION...Shea
Area Forecast Discussion
National Weather Service Corpus Christi TX
624 PM CDT Fri May 14 2021
.AVIATION...
VFR conditions prevail across S TX this evening. MVFR CIGs are
expected to develop across S TX overnight with LRD, COT and ALI
having prevailing MVFR CIGs and VCT and CRP being more
intermittent. The chance for convection will increase across the
western areas overnight, then spread east during the day Saturday.
MVFR/IFR conditions will be possible in and near storms. The best
chance for convection will be across LRD and COT. A weak southeast
flow tonight will become moderate with gusts around 25kt on
Saturday.
&&
.PREV DISCUSSION... /Issued 335 PM CDT Fri May 14 2021/
SHORT TERM (Tonight through Saturday Night)...
Easterly flow off the gulf is beginning to increase moisture
across the area. Dewpoints along the coast have increase into the
upper 60s to around 70. This moisture advection will continue and
enhance through this short term period as flow shifts more around
to the southeast. Rain chances this evening and tonight are
fairly limited as convection expected to develop over the
mountains of Mexico should take a southerly turn as it approaches
the Rio Grande moving along the 850-500mb thickness lines. Some
convection could clip Laredo, but chances are small...will keep
only a 20 PoP.
Going into Saturday, the picture isn`t super clear as models have
been all over the place with expected convection. Before we get
into the details, a little bit of background... A fairly vigorous
upper level shortwave will push across the region from late
tonight through the day on Saturday. PWAT levels remain pretty
unimpressive however, topping out around 1.8 inches which is only
about the 75th percentile and well below 2 standard deviations
above normal. GFS in particular has backed off on QPF
significantly over the past few runs. Meso models are showing
scattered convection,but not widespread. In fact, the 06Z HRRR
model had basically no convection over our entire forecast area
for the daytime Saturday. 12Z came in looking a little better. The
NAM seems to have some convective feedback or suspicious
mesoscale features which has made it seemingly unreliable. That
said... Have lowered PoPs a bit for Saturday period, but will
still keep a high end chance at times, mainly west. CAPE is
sufficient with limited CIN that thunderstorms would be expected
within the convection. Chances spread east for late Saturday into
Saturday night.
Below normal temperatures will continue with abundant cloud cover
developing late tonight and continuing through the end of the
short term period.
LONG TERM (Sunday through Friday)...
No major changes were made from the previous forecast. A series of
shortwave disturbances will push through Texas through the week in
advance of a couple of deeper lows/troughs slowly moving eastward.
Onshore flow will persist at the surface, increasing low-level
moisture with PWATs ranging from 1.5" to 2.0" through the period.
There is still quite a bit of uncertainty regarding the progression
and southern extent of the energy aloft associated with the
disturbances. The majority of energy aloft will be north of us and
if the disturbance shifts further north, then we won`t have much
upper-level support and will lack precipitation potential.
Rain coverage will be sensitive to where shortwaves develop and
where bands of energy aloft drape across South Texas. Yes there`s
moisture in place, but there lacks surface lift while under mostly
cloudy skies. It`s certainly possible that with some isentropic lift
support along with the seabreeze, a few showers and thunderstorms
could develop. If mid and upper-level dynamics become more favorable
with divergence and vorticity in the area, we`ll see rain coverage
increase. At 850mb, winds remain out of the SSE, reducing the
strength of the cap to near none in the afternoon. Instability looks
to be favorable for convection throughout the period, with CAPE
ranging from 1500-3000+ J/kg. Overall, this forecast has a low
confidence in location and amount of precipitation.
Reduced rain chances on Sunday to a max of 60% near the Victoria
Crossroads, latest guidances have shown a greater focus over this
region; scattered showers and thunderstorms over the rest of South
Texas. Only isolated showers and thunderstorms Sunday night through
Monday night as a mid-level ridge between shortwave troughs runs
over the area. Rain chances increase Tuesday as the mid to upper
level low/trough centers over the TX Panhandle, with greatest
chances of rain occurring Tuesday night through Wednesday. Another
shortwave follows in wake of the main low pressure system, allowing
for isolated to scattered showers and thunderstorms through the work
week.
High temperatures will generally range from near 85 over the
Victoria Crossroads to the mid to upper 90s over the Brush Country
through the period. Heat indices may exceed 105F Monday and Tuesday
over the Brush Country. An increase in rain and cloud coverage could
reduce these high temperatures. Lows will remain in the low to mid
70s.
MARINE...
A series of mid to upper level disturbances will combine with
increased moisture to produce isolated to scattered showers and
thunderstorms through the week. There could be a brief break in rain
potential Monday night. Breezy to windy onshore flow will lead to
periods of Small Craft Exercise Caution and Small Craft Advisory
conditions through next week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 72 83 73 84 75 / 10 40 40 40 20
Victoria 67 84 71 82 73 / 10 20 50 60 30
Laredo 73 89 73 95 75 / 30 50 30 20 10
Alice 70 86 72 89 75 / 20 40 40 40 10
Rockport 74 81 74 85 76 / 10 20 40 50 20
Cotulla 72 88 73 93 75 / 20 50 50 30 10
Kingsville 71 85 73 87 75 / 20 50 40 40 10
Navy Corpus 74 81 74 84 76 / 10 30 40 40 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
TE/81...AVIATION
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
634 PM CDT Fri May 14 2021
.AVIATION (00Z TAFs)...
VFR conditions currently prevail across South Central Texas. MVFR
ceilings are forecast to develop 05Z-08Z and then lower to IFR across
the Hill Country, Rio Grande, and into San Antonio metro, including
DRT and SAT. Ceilings are forecast to gradually rise back to VFR
after 18Z. A shortwave will provide for a chance of scattered SHRAs
and TSRA on Saturday. The best chances for convection will be from
DRT to SAT. A tempo TSRA has been included at DRT in the morning and
at SAT in the afternoon.
&&
.PREV DISCUSSION... /ISSUED 239 PM CDT Fri May 14 2021/
SHORT TERM (Today through Saturday)...
After a short break in the clouds over most of the Hill Country and
areas along Interstate 35 late this morning, clouds have built back
into the area. That is because increased moisture continue to arrive
across the region from the Gulf of Mexico. This trend is expected
tonight into Saturday morning and reflected in the overnight lows
which are ranging from the mid 60s to lower 70s. These are the
warmest low temperatures across most areas at least for the last 4
mornings.
There is a slight chance for showers and an isolated thunder or two
across the Rio Grande by day break Saturday. Both global and HiRes
models suggest a mid level short wave moving across the northeast
part of Mexico into the Rio Grande. Latest HRRR solution has the
precipitation to the east and southeast of Del Rio on Saturday
morning. Other HiRes models suggest the activity over the Eagle Pass
area and to the southeast. Also, some ensemble models suggest a mid
level circulation developing near Uvalde and pushing to the
southeast before splitting. Okay, let us break this in three
possible scenarios; one...it could bring heavy rains for Bexar
County and surrounding locations before pushing to the southeast
Saturday afternoon...two...the cluster of storms could miss Bexar
County for the most part with limited rainfall
accumulations...three...the cluster of storms could slowly push
across Bexar County and then splits sending a pulse of energy along
the I-35 and produce a round of showers and storms across the Austin
area late Saturday afternoon. Long story short, we could see little
rain or up to one inch of rainfall with a spot or two with higher
amounts mainly Saturday afternoon and evening. With saturated soils
over many locations from previous rains, any additional rain in a
short period of time could lead to flash flooding.
Hoping to have a better picture overnight with the 00Z data for the
short term period to offer more specifics to you all. Along those
lines, another round of showers and storms is forecast to push
across the Val Verde area on Saturday evening and push to the
southeast. Some of these storms could be strong to severe and
therefore, SPC Day 2 Outlook highlights most areas across the
Edwards Plateau and Rio Grande under a marginal risk for severe
thunderstorms. Also, WPC Excessive Rain Day 2 Outlook highlights
similar area with a marginal risk of rainfall exceeding flash flash
guidance. The wet pattern continues into late next week. More
details below.
LONG TERM (Saturday Night through Thursday)...
An active period is setting up for Saturday night through much of the
following week. As of now it looks like the `worst` day will be
Tuesday evening into Wednesday morning with many questions in the
forecast beyond Wednesday.
At the start of the long term period a shortwave trough will be
moving through the area as a large upper level low pressure system
moves from Southern California into norther Arizona. Other than the
very went 12z ECMWF, the NAM, GFS, and Canadian have shifted much of
the QPF for Sunday to the east as the shortwave exits. If this trend
continues current PoPs for Sunday may be overdone, especially for
areas to the west of Interstate 35. Monday too is generally drier
forecast wise in between the two systems. Areas to the north and east
have the best chances for rain as the shortwave exits. The Canadian
wants to bring a southwestward moving MCS into areas around San
Angelo off of likely outflow boundaries produced by an MCS across
north Texas on Sunday...but this solution is unlikely. While model
soundings show modest CAPE for Monday, many models show a cap
(although a weak one in place for much of Monday).
The `fun` returns on Tuesday. The term `fun` is very much used
loosely here as we have already had a busy spring in terms of severe
weather and Tuesday looks like another busy day. The upper low will
slowly move closer to Texas during the day and be close enough to
provide lift across much of the area. While upper level winds look
more favorable across the Panhandle and to our west over Mexico
forecast soundings are very juicy across much of the area for
Tuesday. Forecast soundings show 2000-3000 j/KG of CAPE and very good
lapse rates. The one limiting factor may be the lack of overall shear
with model soundings only showing 30 knots, as opposed to the typical
60 knots. The overall location of the upper low as it ejects into the
Central Plains late Tuesday may also ultimately come into play. The
GFS remains the strongest solution with a broad upper level low
Tuesday into Wednesday moving across the Texas Panhandle. The ECMWF
and Canadian have the upper low further north, across Colorado and
Kansas. If this solution verifies the better severe chances may be
more to the north on Tuesday. SPC mentioned the threat in their day
4-8 outlook, but wanted to see run-to-run consistency in the models
before drawing an outlook area.
The other big concern will be the heavy rainfall threat. We have seen
several events already this spring with very heavy rainfall rates.
This event looks now different. Precipitable water values from model
soundings and the GFS ensemble all show 1.5 to 1.6 PW values which
are close to or exceeding the seasonal max values. Interestingly the
Ensemble Awareness Tables which show the standard deviations of the
model PW values is not pegging Tuesday yet, but rather showing this
weekend and late in the week as days of higher concern. Regardless
GEFS ensembles are centering around 2-4 inches of rainfall, with 12z
model averages of 3-4 inches through Wednesday. Some higher totals up
to 5 inches are certainly possible, especially when you tack on
Thursday and Friday.
Speaking of Thursday and Friday models differ on how they handle the
shortwave that follows the big upper low. What is certain is that the
rainy pattern will continue.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 66 82 68 81 71 / 0 30 40 60 30
Austin Bergstrom Intl Airport 65 82 68 81 71 / 0 30 40 60 30
New Braunfels Muni Airport 66 83 69 83 72 / 0 40 40 60 30
Burnet Muni Airport 65 80 67 80 69 / 0 30 50 60 30
Del Rio Intl Airport 70 85 70 89 73 / 10 50 50 30 10
Georgetown Muni Airport 64 82 67 81 70 / 0 20 40 70 30
Hondo Muni Airport 67 82 68 85 72 / 10 60 50 40 20
San Marcos Muni Airport 65 82 68 82 71 / 0 30 40 60 30
La Grange - Fayette Regional 65 85 70 83 73 / 0 10 30 70 30
San Antonio Intl Airport 68 82 68 83 71 / - 50 50 50 30
Stinson Muni Airport 69 83 70 84 72 / - 50 50 50 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...Runyen
Long-Term...Oaks
Decision Support...33
Area Forecast Discussion
National Weather Service Grand Forks ND
1001 PM CDT Fri May 14 2021
.UPDATE...
Issued at 1000 PM CDT Fri May 14 2021
From satellite, 500 mb system near Bemidji. Pocket of lower clouds
near this rotating around Bemidji/Waskish area. Remaining showers
just west of Grand Forks weakening as are the leftover showers in
far NW MN. Atmosphere not condusive for continued showers
overnight so will continue to see slow weakening.
UPDATE Issued at 713 PM CDT Fri May 14 2021
Showers and thunderstorms are diminishing after peaking in
intensity between 430 and 630 pm. Slow diminishing trend this
evening will continue. 500 mb short wave moving very slowly and
is near the SD/MN/ND border and this area did have more
instability and a bit more coveage of storms and storms with
mainly small hail. Shower/t-storm chances will diminish thru
midnight. Cloud cover Bemidji to Park Rapids area prevented as
much heating and that area has seen little in the way of rainfall
today and this trend should continue. Will update pops a bit for
current and forecast thoughts.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 339 PM CDT Fri May 14 2021
Isolated severe thunderstorm potential this afternoon/early evening
over the far southern RRV into west central MN, with primary threats
1" hail and winds to 50 mph. There is also a very low potential for
funnels or even a non supercell tornado near the SD state line this
afternoon (very low confidence in occurrence/impacts).
700 MB close low and associated mid level vorticity advection is
moving over our CWA, and with peak heating/steep low level lapse
rates clusters of showers/weak thunderstorms have developed. RAP
objective analysis indicates MU CAPE values with elevated parcels
near 1000 J/KG in our far south, with effect shear values under
20kt. Freezing levels between 6500-8000 FT AGL is low enough that it
shouldn`t take a particularly tall updraft to produce at least small
hail if not a few isolated reports of 1" hail before sunset. DCAPE
is minimal (around 500 J/KG), so while severe wind isn`t anticipated
there is still potential with inverted-V type soundings for wind
gusts 40-50 mph with taller cores. Storm motions are tending to be
very slow with variable motions due to low shear and mid level
center overhead. Mid level lapse rates/cold pool aren`t
particularly impressive, but with this rotation in place and
surface vorticity increasing in our south there is a very low
potential for a few funnels. Non supercell tornado parameter is
positive near the SD where 0-3km CAPE and surface vorticity are
maximized and "if" there was a funnel in this environment there
may be enough stretching for brief tornado development. This is
highly conditional/uncertain and not an ideal set up. Still, worth
monitoring thorugh the peak heating period of the afternoon (next
few hours).
We should see a rapid decrease in intensity and eventually coverage
with the loss of daytime heating. Eventually the the shortwave moves
east and any lingering showers in our east should taper off. There
are a few subtle mid level impulses Sunday near the International
Border that may spark a few afternoon showers (very light) otherwise
drier conditions are expected again. Warm temperatures continue and
with less cloud cover potential is there for most locations to reach
the 70s if not close in on 80 within the RRV (near 70 favored in the
east). This may also result in lower RH values in the 20-30 percent
range, but with lower wind (gusts generally around 15 mph) near
critical fire weather is currently not anticipated (will monitor).
.LONG TERM...(Sunday through Friday)
Issued at 339 PM CDT Fri May 14 2021
Warmer temperatures and rain chances dominate the forecast for next
week.
After this weekend`s rain chances, the upper levels shift into
a ridging pattern. This will be conducive to warming temperatures
getting into the 80s and quiet weather for the first half of the
work week.
Once we reach mid-week, rain chances return to the
region. Showers and thunderstorms will be possible for the remainder
of the forecast period as a low pressure system develops to our west
and then moves into Canada. Precipitation amounts appear to be
minimal in the ensembles. Guidance is not conclusive on timing,
path, and amounts but will start to get a better handle on the event
as we get closer in time. Rain will not do any good for our
temperatures though, as highs are expected to remain in the upper
70s and low 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 713 PM CDT Fri May 14 2021
Bemidji area in a region of MVFR clouds and tendency for these to
hold steady thru the night. Otherwise VFR thru the pd with
scattered cloud layers, CU field in the 6000 ft agl range with
some mid and high level moisture above. Winds this evening south-
southeast RRV and east and more northeast to north west of the
RRV as weak surface low moves through. Trend will be for all winds
to diminish to 5 kts or less overnight and be variable even into
Saturday daytime.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$
UPDATE...Riddle
SHORT TERM...DJR
LONG TERM...AK
AVIATION...Riddle
AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
1035 PM CDT Fri May 14 2021
.SHORT TERM...(This Evening through Saturday)
Issued at 245 PM CDT Fri May 14 2021
Focus for the remainder of the daytime hours will be on a weak
surface trough/wind shift currently located across central SD. Mid
afternoon RAP mesoanalysis suggests a ribbon of 100-300 J/kg of
MLCAPE and perhaps up to 1000 J/kg of SBCAPE near and ahead of
this convergence zone with a bubbling Cu and weak radar returns
from NE SD to Huron to Winner. Earlier outlooks from SPC had
highlighted areas just west of I-29 in a Marginal risk for severe
weather although with effective shear running around 35 kts or
less (and high cloud bases), organized severe weather seems
unlikely and that risk area was removed in the mid-day issuance.
With that said, in the presence of a relatively low freezing level
and marginal instability, can`t completely discount the idea of a
stronger storm or two producing hail approaching severe criteria.
Additionally, winds through the lowest 10-15 kft are fairly light
so not much to mix down, however inverted-V-type soundings may
allow for an occasional gust up to 40 mph with any stronger
activity. This all should be largely diurnally driven and thus
suspect after sunset a rapid decrease in any activity that may
exist.
Overnight period may bring some fog to the region with a moistened
boundary layer and light winds. High-res guidance has varying
degrees of this potential with SREF probabilities highest east of I-
29. Could see some mid-upper level clouds overhead as well which
would likely temper this fog potential. Have added in some patchy
mention for now and will monitor trends going forward.
We should be able to shake any morning cloud cover/fog by mid to
late morning with a fair amount of sunshine by Saturday afternoon.
With some weak uncapped surface based instability, may also see
additional Cu bubble up. A handful of the high-res guidance tries to
generate some weak convection under these conditions and thus have
introduce some slight chance POPs. With some upper level subsidence
by mid to late afternoon, this seems like a low probability scenario
however. Otherwise, widespread temperatures in the 70s expected.
.LONG TERM...(Saturday Night through Friday)
Issued at 245 PM CDT Fri May 14 2021
A compact wave may allow for a blossoming area of showers and
thunderstorms off of the Black Hills by Saturday night that will
drift eastward into Sunday morning. However with the better
instability shunted well south, these will likely have a fading
tendency as they approach our area. Additionally, this wave
generally shears/weakens through the day Sunday and while can`t
discount some low end chance level POPs for Sunday, the better
chances appear to be from the MO River Valley and points south.
Temperatures again a few degrees either side of 70 although any
lingering precipitation may contaminate temperatures as well.
Northern stream jet pushed into Canada for early next week with
broad ridging as a cutoff low fills across the Desert Southwest.
Some indication that a fractured southwest flow regime sets up by
Tuesday into next week that may lift various disturbances into our
area but with an interrupted moisture and instability plume wouldn`t
expect anything in terms of any significant convection. Timing in the
arrival of these shortwaves is also inconsistent from model to model
and run to run leading to a smeared period of POPs that are likely
too robust temporally. In other words, would characterize this period
as potentially active in terms of precipitation but far from a
washout. Temperatures will again be dependent on precipitation
timing/coverage but 70s seem like a good starting point for highs.
Perhaps some better signal for west coast upper level troughing by
late in the week which should help to usher higher moisture content
air into our region which is also denoted by PWATs finally sneaking
into the upper quartile of climatology. This may also provide some
modest increase in our severe weather chances which is also
reflected in CIPS analogs.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1030 PM CDT Fri May 14 2021
Scattered convection will continue across portions of southwest
Minnesota into the early overnight hours as a subtle wave moves
through. Elsewhere, VFR conditions continue into the overnight
hours.
Fog probabilities have fallen slightly due to the increased cloud
cover, and have backed off slightly in current TAFs.
Winds will remain light on Saturday, with the quick development of
a CU field by mid-day and through the afternoon. Should convective
temps in the 70s be met, then a few pop-up storms could be
possible.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...Kalin
LONG TERM...Kalin
AVIATION...Dux
Area Forecast Discussion
National Weather Service Goodland KS
925 PM MDT Fri May 14 2021
.UPDATE...
Issued at 924 PM MDT Fri May 14 2021
The severe thunderstorms watch for the area has been cancelled.
The area of severe storms has moved out of the area and no
additional severe storms are expected to move into the area during
the remainder of tonight.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 243 PM MDT Fri May 14 2021
Satellite and 500 mb RAP analysis showed northwest flow over the
region early this afternoon, with a shortwave moving into Colorado.
Weak ridging was observed from the Four Corners region up towards
the Great Basin. Mid to high level clouds developed off the Rockies
as the shortwave approached, gradually pushing into the region while
storms form along the Front Range. At 2 PM MT, northeast winds were
observed at 10 to 15 mph with temperatures in the upper 60s to low
70s.
A few thunderstorms are expected to move into eastern Colorado
during the mid to late afternoon hours. Storms are expected to
increase in coverage (likely becoming a cluster or two) as they
progress east into northwest Kansas and extreme southwest Nebraska
during the evening hours and the shortwave kicks through the area.
Shear near 40 knots (increasing to near 60 knots in the evening),
CAPE of 1000 to 2000 J/kg, and steep lapse rates will support severe
thunderstorms this afternoon and evening. The main hazards initially
appear to be large hail and damaging winds. Although a tornado
cannot be ruled out, dry air at the surface and high LCLs will
really limit tornado development for this event. As storms
transition to a complex tonight, concern turns more towards a
damaging wind and heavy rainfall threat. PWATs nearing 1 inch
(with 1.25" not out of the question for eastern portions of the
area), suggest that locally heavy rainfall will need to be
monitored. Thunderstorm activity slowly exits the region to the
east/southeast overnight into early Saturday as temperatures fall
into the mid 40s to mid 50s.
Another point to quickly mention...There appears to be a signal
for fog returning to the region late tonight into early Saturday,
although it looks more widespread than previous nights. The fog
and stratus are forecast to set in after midnight. Reduced
visibilities could cause hazardous travel for the morning commute.
However, locations that will be most impacted is uncertain at
this time.
For Saturday, some guidance shows showers and storms lingering along
the Nebraska border and eastern part of the area into the morning
hours. There should be a lull midday before another round of
thunderstorms develops in the afternoon. The setup will be similar
to today. Looks like a few storms will initiate along a surface
trough in eastern/central Colorado during the afternoon before
pushing east and forming a cluster once again. While shear appears
to be lower, steep lapse rates and good instability indicate that
large hail and damaging winds are potential hazards. Otherwise,
expect highs in the upper 60s to low 70s tomorrow, and lows in the
50s Saturday night.
.LONG TERM...(Sunday through Friday)
Issued at 155 PM MDT Fri May 14 2021
The long term period is looking unsettled with near constant chances
for rain through the week. Temperatures look to be near average with
highs around 70.
Sunday starts with slight ridging aloft at 500mb that will
transition to more of a laminar flow out in front of an advancing
cut-off low. The cut-off low will then slowly move towards and into
the area during the early week before diffusing out into the larger
flow. The end of the week looks to have the ridge set up over the
Eastern CONUS while a trough moves into the Western CONUS. This
pattern may provide some slight synoptic support for storms but
looks to be relatively weak in flow and potentially even split the
flow.
Near the surface, the Tri-State area appears to be between two
larger areas of high and low pressure with higher pressure to the
east under the upper ridge and lower pressure to the south and west
as the cut-off low moves closer to the area. With lower pressure to
the south, moisture is forecasted to be pulled from the Gulf of
Mexico north into the area. The question becomes how much of this
moisture will be realized and actually pulled into the area.
Guidance has been shifting the lower pressure further south in more
recent runs and the precip appears to be shifting south with it.
Also making things more interesting is a nearby cold front that
passes through Sunday and cools temperatures slightly going forward.
What all of this means is that the current forecast calls for rain
and storms for most of the week with the greater rain chances and
amounts currently arriving on Sunday after the front. The rest of
the week may have similarly high chances, but confidence in
coverage and higher rain amounts is low due to the general
shifting of the lower pressure south. Without the support for lift
and if cloud cover from the system in the area limits daytime
heating, storms will likely be lesser in coverage and intensity.
Temperatures are expected to be relatively steady until the end of
the week with highs forecasted in the 60`s and 70`s. There could
be some variations due to cloud cover or lack there of in certain
locales but this will be clearer as each day gets closer. While
severe threat currently looks to be low for much of the week,
there could still be a chance if clouds break for daytime heating.
There also could be a chance next weekend as a similar setup to
recent days is appearing in guidance with a Front Range low and
southerly flow bringing moisture north. Still plenty of
uncertainty with that solution.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 510 PM MDT Fri May 14 2021
GLD will remain VFR as thunderstorms move through the vicinity
between 01-06Z this evening. Expect -TSRA to be a prevailing
conditions between 03-04Z with intermittent moderate to heavy rain
along with gusts to 45kts as storms are expected to pass over the
TAF site. After storms pass, conditions are expected to
transition to IFR between 10-15Z due to low ceilings and areas of
fog that will bring visibility down to around 2 miles. Fog is
expected to dissipate with lifting ceilings by 15Z with a
transition up to MVFR conditions followed by VFR conditions after
20Z.
MCK will have VFR conditions with thunderstorms moving through the
vicinity between 03-08Z. A short period of more storms moving
across the site is expected between 03-04Z with moderate to heavy
rain and wind gusts to 40kts. Between 08-14Z, conditions are
expected to drop to IFR due to lowering ceilings and areas of fog
that will bring visibility down to around 2 miles. Conditions
improve to MVFR after 14Z as fog dissipates and ceilings raise,
and VFR after 19Z and ceilings continue to raise.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...JBH
LONG TERM...KAK
AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Gray ME
1029 PM EDT Fri May 14 2021
.SYNOPSIS...
After a cool and calm night tonight, warm weather continues
over the weekend into early next week, although healthy sea
breezes will develop during the afternoons and keep conditions
cooler near the coast. We will be in a pattern over the weekend
into next week where abundant morning sunshine will lead to
enough instability to bring chances for afternoon showers and a
few thunderstorms each day.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Update...
Isolated showers will continue to diminish across the forecast
area per latest radar imagery as of 0238Z. Just about all of the
precipitation is not reaching the ground late this evening as
surface dew points remain very low this evening. The latest HRRR
has this precipitation diminishing as well over the next hour.
Temperatures will be monitored closely this evening as there
will be rapid drops in readings overnight as winds decouple
under clearing skies. Frost at this time should be limited
however over central sections and mainly confined to northern
zones which have yet to set the frost/freeze program.
Prev Disc...
After a warm day today, with spotty showers providing brief
wind gusts to 20-30 mph, winds will calm and temperatures will
cool into the upper-30s to mid-40s tonight. While low dewpoints
today, in the upper-20s to mid-30s at this hour, leave plenty of
room to drop tonight, I do anticipate lingering cloud cover and
a few-millibar surface PGF to prevent temperatures from
cratering too much tonight. At any rate went with the coolest
guidance, but no lower. Will have to watch trends in guidance in
case a frost advisory becomes necessary, at this juncture most
likely for the Connecticut River Valley.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Tomorrow will be awfully reminiscent of summertime for the
region. Temperatures are expected to warm quickly into the 70s
late in the morning, perhaps flirting with 80 over interior
southern New Hampshire. High pressure however will be overhead
with a weak PGF... which will open the door for a healthy sea
breeze to form early, slowing the warming trend along the coast.
Regardless, the warmth and initially mostly sunny skies,
coinciding with the fact that it`s Saturday, will likely
encourage many to flock to the mountains, lakes, and beaches.
Since inland lake and oceanic temperatures remain in the
upper-40s to low-50s, a Beach Hazard Statement was coordinated
with the USCG along the New Hampshire Seacoast and the southern
and Mid-coast of Maine. An information statement for inland cold
water will be issued later this evening.
Besides those sensible weather impacts, am also expecting
another day of diurnally driven shower and thunderstorm
activity. Showers start to pop mid- to late-morning along a zone
of convergence over western Maine, then grow in coverage through
the day, coming to an end late in the evening. An upper level
wave over Quebec will provide some upper level support, and also
steepen lapse rates a bit aloft, which will allow for greater
coverage in and north of the mountains into central Maine. These
will again be capable of producing gusty winds with dry low-
levels offering a few hundred J/kg of DCAPE... although tall-
skinny CAPE and weak shear don`t offer much in the way of
updraft strength or duration. Dry air remaining over the
Connecticut River Valley into extreme southwest Maine will make
it tougher for these showers to form, let along reach the
ground.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Overview...The first half of the long term looks decidedly more
active than the first half as a weak frontal boundary lingers near
or over the region. A frontal passage on Tuesday should bring an end
to the daily chances for showers and thunderstorms Sunday through
Tuesday. Some of the stronger storms on Sunday (and possibly on
Monday and Tuesday as well) could produce gusty winds and small
hail. Temperatures look set to warm up well above normal through mid-
week before potentially coming back closer to normal toward the
second half of the week.
Impacts...Stronger storms on Sunday could produce gusty winds and
small hail. These hazards will again be possible in any stronger
storms on Monday and Tuesday.
Forecast Details...Looking at the first half of the long term,
expecting the bulk of any precipitation over the period to fall over
these three days. All of this will occur from showers and
thunderstorms, so not expecting widespread significant amounts with
some locations receiving more then others...typical of diurnal
convection.
Sunday remains the most favorable day for both coverage of showers
and thunderstorms and potential for stronger storms to produce gusty
winds and small hail. Isolated thunder looks possible all the way
down to the coast, though any inland progression of the sea breeze
may ultimately hinder any storms that manage to make it there. The
best chance for thunder will be in northern and western areas...and
these areas are the best best to see any gusty winds or small hail
from any storms. All activity should diminish pretty quickly with
the loss of daytime heating. Monday looks similar to Sunday, but
with less upper level support from building ridging aloft, not
expecting quite as much coverage or intensity compared to Sunday.
Northern areas again stand the best chance to see thunder and
potentially gusty winds or small hail.
Tuesday sees the passage of a cold front with yet another chance for
showers. Do think that there could be a few thunderstorms as
well, mainly along the international border. After the frontal
passage, the remainder of the period looks rather dry with
perhaps some afternoons showers possible on Wednesday and
Thursday.
Temperatures will be on a gradual warming trend into mid-week with
the warmest temperatures of the season possible on Wednesday and
Thursday.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR for all terminals through tonight with gusty
west to northwest winds today going light and variable to calm
tonight. A general westerly wind after sunrise tomorrow will
relent to onshore flow for coastal terminals by mid-morning,
reaching interior locations like AUG/MHT/CON by mid-day. Brief
restrictions are possible in -SHRA/isolated TSRA during the
afternoon and evening hours with greatest likelihood of this
occurring at KAUG and KHIE... least likely for southern
terminals.
Long Term...VFR conditions expected at all terminals, outside of
any brief restrictions from showers or thunderstorms. With high
pressure dominating, winds will generally be light.
&&
.MARINE...
Short Term...High pressure gradually moves out over the waters
through tonight and into tomorrow, which will keep seas and
winds suppressed below SCA thresholds. Otherwise afternoon and
early evening showers forming over land may track over the
coastal waters before dissipating today and tomorrow with a low,
but non-zero, change for a thunderstorm.
Long Term...Winds and seas expected to remain below small craft
criteria through the period. There is a chance that a few
isolated showers, and possibly a thunderstorm or two, affect
the waters Sunday and Monday afternoons.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement from 8 AM EDT Saturday through
Saturday evening for MEZ023>028.
NH...Beach Hazards Statement from 8 AM EDT Saturday through
Saturday evening for NHZ014.
MARINE...None.
&&
$$
NEAR/SHORT TERM...Cannon
Area Forecast Discussion
National Weather Service Wichita KS
656 PM CDT Fri May 14 2021
.SHORT TERM...(This evening through Sunday night)
Issued at 317 PM CDT Fri May 14 2021
Currently have northwest flow aloft over the Plains with weak
upper troughing over southern CA. At the surface, high is situated
over the Ohio Valley with return flow ramping up across the
Southern Plains. There looks to be a weak warm front stretching
from NW KS into far southern Nebraska.
Elevated storms lingered this morning over south central KS with
additional development early this afternoon near Wichita. This
activity is making it`s way off to the southeast with the stronger
storms producing small hail. This activity has been driven by
persistent theta-e advection in the 700-600mb layer and should
continue to push east late this afternoon and weaken as it runs
into less instability.
Storm are then expected to develop out over western KS/eastern CO
early this evening due to increasing low level moisture over this
area along with some upslope enhancement. Weak warm front will
also remain situated over northwest KS which could help increase
convergence necessary for initiation. Anything that develops out
west will track east/southeast tonight. In addition, 850-700mb
moisture transport looks to ramp back up after dark and will
either help storms hold together as they track east or allow for
additional development. 1000-1500J/KG of elevated CAPE and
25-30kts of effective shear should allow for some low end severe
criteria for the stronger storms tonight. Right now it appears
this activity would reach the Wichita area generally after 1 am.
Very difficult convective forecast setting up for Sat, as much of
it will depend how widespread storms are tonight and how far south
the weak cold front ends up being pushed. Right now going with the
thinking that overnight elevated activity will be moving into
eastern KS by the late morning hours with a lull in activity Sat
afternoon. Then expecting the potential for storms to develop
along the front near the KS/OK border late Sat afternoon or early
Sat evening. While feel the better chances for surface based
storm initiation Sat will be further west over the high Plains,
can`t rule out a few storms over far southern KS due to lack of
capping and plenty of instability. Even with less than ideal shear
for severe storms, still feel there will be enough instability
for any storm that develops to become severe.
There looks to be some model agreement on slowly lifting an upper
impulse out of the southern High Plains Sat evening and across
central/eastern OK during the day Sun. This will keep showers and
storms in the forecast for Sun morning with the better chances
moving into eastern KS by Sun afternoon/evening.
.LONG TERM...(Monday through Friday)
Issued at 317 PM CDT Fri May 14 2021
By Mon morning, upper impulse will be lifting into MO with a
closed upper low slowly migrating across the Desert Southwest. So
we may see a lull in activity for Mon as our forecast area will be
in-between the two low pressure systems. Southwest CONUS upper
low will start to directly impact the forecast area late Mon night
with the highest precip chances looking like Tue night into Wed
as we get into an area of decent upper diffluence. While
confidence is high we are not looking at a widespread severe
weather episode, it`s tough to completely rule out a strong or
severe storm given the time of year. Should see another overall
decrease in storm potential for Thu afternoon into Fri as the
shortwave lifts off into the Upper Mississippi Valley.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 653 PM CDT Fri May 14 2021
Challenging aviation forecast with location/timing of storms and
potential for MVFR or IFR ceilings late tonight and Saturday
morning.
Best estimate based on recent high resolution models and
verification of said models last night, suggest a line or cluster
of storms will traverse the KGBD-KHUT-KCNU axis late this evening
and overnight fairly quickly. Uncertainty will result in at least
a mention of storms at all sites during the night. Beyond that
confidence dwindles. Much of the ceiling issues revolves on
boundary layer moisture forecasts, of which HRRR is one of the
driest and many are quite moist. Suspect the higher relative
humidity is a function of model bias to over saturate boundary
layer in upslope flow. Given skepticism opted only to go MVFR for
now. Also some potential for showers to develop along and north
of outflow boundary or along elevated front late tonight and into
the morning, but lack of confidence resulted in VCSH at most. -Howerton
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 58 72 61 72 / 70 50 70 70
Hutchinson 57 72 59 72 / 80 40 60 70
Newton 57 70 60 72 / 80 50 70 70
ElDorado 57 70 60 72 / 80 60 70 80
Winfield-KWLD 58 74 62 72 / 50 60 70 80
Russell 56 72 56 72 / 80 30 50 70
Great Bend 56 73 57 72 / 80 30 60 70
Salina 56 72 58 72 / 80 40 60 70
McPherson 56 71 59 72 / 90 40 60 70
Coffeyville 56 73 61 73 / 70 70 80 70
Chanute 56 68 61 72 / 90 80 70 80
Iola 55 67 60 72 / 90 80 60 80
Parsons-KPPF 56 71 61 72 / 80 70 70 70
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...RBL
LONG TERM...RBL
AVIATION...PJH
Area Forecast Discussion
National Weather Service Marquette MI
634 PM EDT Fri May 14 2021
.SHORT TERM...(This evening through Saturday)
Issued at 327 PM EDT FRI MAY 14 2021
Latest WV imagery and RAP analysis reveals a shortwave moving across
the Upper Great Lakes with maybe another couple of shortwaves
upstream over the Dakotas and eastern MT. Increased mid-level
moisture and weak forcing from the shortwave moving over the area
combined with merging lake breeze boundaries have resulted in the
formation of isolated showers over mainly the east half of the U.P.
this afternoon. There were even a couple of lightning strikes over
portions of southern Schoolcraft County. Generally expect these
isolated showers to continue over the east half of the U.P. into
early evening as MLCAPEs remain in the 100-200 j/kg range. Deep
mixing over the interior west half has resulted in dewpoints in the
low 20s with min RH values lowering to around 20 pct. Light winds
however will ease fire wx concerns. Highs across the area have
generally been in the 60s, although a few spots have topped the 70F
mark.
Tonight, any showers and most of the clouds will diminish during the
evening. Expect enough radiational cooling overnight to drop min
temps to around 40 inland and to the mid and upper 40s along Lake
Superior where weak downslope southerly flow prevails. Shower
chances associated with an approaching the west ahead of an
approaching shrtwv and sfc trough should hold off until Saturday.
Saturday, next shortwave approaches from the western/northern
Plains. Weak isentropic ascent and theta-e advection ahead of the
shortwave should result in scattered light showers, especially
west half and south central portions in the afternoon. Expect
highs to range from the lower to mid 60s west half under more
clouds to the upper 60s east where there should be a bit more sun.
More sunshine east should result in deeper mixing, lowering min
RH values into the 20 to 25 range. The dry conditions combined
with a bit stronger, and perhaps gustier, southerly gradient winds
could result in borderline elevated fire weather concerns over
the eastern counties on Saturday.
.LONG TERM...(Saturday night through Friday)
Issued at 534 PM EDT FRI MAY 14 2021
The medium to extended forecast will trend toward normal to above-
normal temperatures, and near normal precipitation chances for the
next two weeks. Zonal to upper level ridging will be present over
the Great Lakes overall, with multiple shortwave disturbances riding
along the flow to create the opportunity for occasional showers at
times, but not amounting to much for precipitation.
Saturday night through Sunday night will trend towards a couple of
shortwave disturbances riding along the 500mb upper level zonal
flow. The zonal flow will trend toward weak ridging, thus allowing
temperatures to remain warm on Sunday. PWATs look rather low for the
moisture source on Sunday afternoon/evening as the shortwave
propagates aloft with 0.5-0.75". A few vorticity maxes may propagate
through the area enhancing the dynamics for any showers that develop
over Upper Michigan, but wind shear isn`t there to assist with
stronger convection development at this time...so likely to be more
of the same as Saturday with showers. Upper level ridge will begin
to intensify on Monday over the Great Lakes, limiting chances of
diurnal shower activity from occurring, albeit warmer temperatures
can be expected to start the week.
An upper level low will become closed off from the main jet energy
on Sunday/Monday over the 4 corners region of the CONUS, so there
will be temporary split flow aloft between the northern and southern
streams of jet energy. As this upper level low slowly propagates
over the 4 corners to the southern Rolling Plains from Monday into
Tuesday, it will begin to be absorbed back into the main jet energy.
This will allow for a shortwave trough to become negatively tilted
over the Central CONUS. At the same time of the shortwave trough
deepening, the potential increases for a weak omega block feature to
develop as an upper level ridge will become elongated from the
southeast further upstream toward the Great Lakes/Canadian
Provinces. Model guidance begins to differ by Wednesday, with
different signals of where the placement of possible convection over
the Upper Mississippi Valley and Great Lakes may occur.
Trends continue with warm temperatures from Monday into next weekend
where chances of afternoon convection and above average temperatures
are possible for the latter portion of the week. Long range guidance
of 850mb temperatures over Upper Michigan on Thursday through
Saturday are upwards of 18C-20C. This would easily put diurnal
maximums at the 80+ degree threshold for several areas across Upper
Michigan. We will continue to monitor the long range guidance in the
event that signals for more organized convection with the weather
system next week look marginal or better.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 633 PM EDT FRI MAY 14 2021
VFR conditions will continue at CMX and SAW through the forecast
period. IWD will be VFR into Sat morning before MVFR cigs come in
with a small chance for showers Sat afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 327 PM EDT FRI MAY 14 2021
High pressure will remain over the Great Lakes for the next several
days, limiting wind gusts over the lake to 15 knots or less
into much of next week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...BW
AVIATION...07
MARINE...Voss