Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/02/19
Area Forecast Discussion
National Weather Service Denver/Boulder CO
833 PM MDT Thu Aug 1 2019
.UPDATE...
Issued at 833 PM MDT Thu Aug 1 2019
The intensity of thunderstorms has decreased by the coverage of
storms remains high on the eastern plains with scattered
thunderstorms still generating over Weld County and the northern
Front Range foothills. The Severe Thunderstorm Watch has been
cancelled, but areas covered by the Flash Flood Watch are still
receiving light to moderate rainfall, some of which is falling on
areas that received heavy rain earlier this evening. Will let the
Flash Flood Watch continue. A very moist airmass remains in place
across northeast Colorado with dew points in the lower to mid 60s.
Precipitable water values are also still in the 1.00 to 1.25 inch
range. Sub-tropical moisture at mid levels will continue moving
over central Colorado and out over northeast Colorado through the
night, keeping shower activity going for a few more hours. After
midnight, the airmass should stabilize with drier and more
subsident air expected to move in from northwest Colorado and
south-central Wyoming. Quick look at the evening models shows a
much drier day tomorrow with increasing northerly flow at mid and
upper levels, due to the center of the upper level ridge sliding a
little bit to our west and southwest.
As the shower activity on the plains dissipates later tonight, the
Flash Flood Watch will be allowed to expire.
&&
.SHORT TERM...(This evening through Friday)
Issued at 245 PM MDT Thu Aug 1 2019
Plume of monsoonal moisture is pushing east across the forecast
area, with showers and storms becoming more numerous. Convection
has been a little slow to develop due to the abundant sky cover
over the high country. Strongest convection is now just developing
over the plains east of I-25 as expected, thanks to more sunshine
there.
This evolution will continue through the evening, with the
strongest storms developing and spreading east across the plains.
Convection will become more widespread there with the upslope
flow, moderate to high instability of MLCAPE near 2000 J/kg, and a
passing upper level disturbance bringing weak but deep lift. As
the low level jet strengthens this evening, we expect further
development into a Mesoscale Convective System (MCS) on the
eastern plains. Locally heavy rainfall and flash flooding threat
will continue there until about 10 PM - Midnight...see Hydrology
section below for more details. A couple severe storms expected
too, with wet microbursts and strong winds up to 60-70 mph
possible. Along the Front Range Foothills and I-25 Corridor, the
intensity of storms will be limited by instability. Brief heavy
rain can still be expected through the mid evening hours as
precipitable water values are quite high, near 1.25 inches. Storms
will be moving along at 15-20 mph here, so generally minor if any
flooding expected from a stronger storm moving through a burn
scar or urban area.
For later tonight, skies will generally clear from west to east as
the short wave passes and weak subsidence builds in.
On Friday, the latest data indicates a cap to remain in place
across most of the plains, so we`ll reduce/remove chance of
storms over all of the plains. Main chance of afternoon storms
would stick to the higher elevations and mountains west and
southwest of Denver where cap should be broken thanks to elevated
heating source. Temperatures near normal.
.LONG TERM...(Friday night through Thursday)
Issued at 329 PM MDT Thu Aug 1 2019
The upper ridge will be centered right around the four corners
Friday night through Sunday night. The flow aloft will be light
and west-northwesterly. The QG Omega fields show subsidence in the
synoptic scale for much of the CWA Friday night. There is neutral
energy progged Saturday through Sunday, with a tad of weak upward
energy Sunday night. The low level winds look to be easterly
Friday evening, with normal drainage patterns kicking in
overnight. Decent east-southeasterlies are progged Saturday and
again Sunday with normal drainage patterns Saturday and Sunday
nights. Concerning moisture, precipitable water values are mostly
progged below 1.00 inch over much of the CWA Friday night into
Sunday morning. They come up a tad Sunday and Sunday night. The
surface dew points stay mainly in the 50s F over the plains for
the five periods, with a few lowers 60s along the eastern border.
There is fairly decent CAPE around over the mountains and
foothills Friday evening. For late day Saturday, the best CAPE is
over the southwestern and far eastern CWA. The decent CAPE on
Sunday is relegated to the high country. The QPF Fields show
measurable rainfall mainly over the mountains and foothills Friday
evening, late day Saturday and late day Sunday. For pops, will go
with "scattered"s over the mountains and foothills Friday
evening. Same for late day Saturday with the additions of the
Palmer Ridge. For late day Sunday, with go with "scattered"s for
the western 3/5ths of the CWA. For temperatures, Saturday`s highs
are 1-2 C warmer than Friday`s highs. Sunday`s highs are about 2 C
warmer than Saturday`s. For the later days, Monday through
Thursday, models keep the center of the upper ridge southwest of
Colorado through Tuesday, then due south of the state Wednesday
and Thursday. The ridge axis is over western Colorado on up into
Canada. The mid and upper level moisture is progged to stick
around and precipitable water values are generally above 1.00 inch
over the plains all four days. Temperatures stay right at
seasonal normals.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 833 PM MDT Thu Aug 1 2019
A few lingering showers may still move across the Denver area
through about 10 PM. After that skies should begin to clear as
showers dissipate. There is a chance that areas of stratus or fog
will develop due to the airmass being so wet. The HRRR brings fog
to KDEN and the South Platte River Valley between 3 AM and 8 AM.
Surface winds are expected to be sioutherly or southwesterly which
would tend to be drying on the local scale. Will mention some fog
in the vicinity for few morning hours with the next set of
forecasts. No other aviation impacts are expected through tomorrow
afternoon as the winds turn northerly and drier, more stable air
moves into the region.
&&
.HYDROLOGY...
Issued at 245 PM MDT Thu Aug 1 2019
All satellite imagery shows the monsoonal moisture plume shifting
east across the forecast area, coinciding with peak heating and
destabilization. Strongest storms have developed just east of the
I-25 Corridor, where bulk of instability exists and cap has been
broken. The main threat for more significant rainfall and flash
flooding will remain in that area this evening as favorable
parameters on the eastern plains include; lower to mid 60s surface
dewpoints, increasing easterly low level jet into the evening,
high PWs with values of 1.3-1.5 inches, deep warm cloud depth of
6,000-9,000 feet, and the expected development of an Mesoscale
Convective System (MCS). Storm totals of 2 to 4 inches are
possible from the stronger storms, with rainfall rates of 1 to 2
inches in about 30 minutes. Flash flooding will be possible
especially over locations that have received heavy rainfall over
the past couple of days, or those areas that see training storms
on the edge of the expected MCS. The Flash Flood Watch for a good
portion of the northeast Colorado plains from 4 PM to Midnight
looks on track.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until midnight MDT tonight for COZ042-044>046-
048-049.
&&
$$
UPDATE...Dankers
SHORT TERM...Barjenbruch
LONG TERM...RJK
AVIATION...Dankers
HYDROLOGY...Barjenbruch
Area Forecast Discussion
National Weather Service Goodland KS
920 PM MDT Thu Aug 1 2019
.UPDATE...
Issued at 917 PM MDT Thu Aug 1 2019
The window for severe weather has closed for today as the
environment has stabilized enough to cap off any CAPE. Am
expecting the light/moderate rainfall to slowly move east through
the night. As it moves east it will shift more toward the central
part of the forecast area where the LLJ nose will be that will
also be moving east. Current forecast has chances for rainfall
lingering past sunrise. Am thinking the storm activity should be
east of the forecast area by 4 AM or 5 AM MT.
&&
.SHORT TERM...(Through Tonight)
Issued at 135 PM MDT Thu Aug 1 2019
Light W-WNW flow aloft persists over the region, on the N-NNE
periphery of an upper level ridge.
Pervasive low stratus, light northerly flow, and transient
elevated showers throughout the morning have profoundly attenuated
insolation across the Tri-State area. Given significant
convective inhibition (100-300 J/kg CINH) and weak/limited
forcing confined to shallow low-level convergence, convection is
not anticipated to initiate over the Tri-State area this
afternoon. Convection developing along the Colorado Front Range
between 19-22Z is anticipated to gradually propagate downstream
into eastern Colorado late this afternoon (00-03Z) and into
western Kansas this evening (03-06Z) -- as indicated by simulated
reflectivity forecasts via multiple runs of the HRRR and NAM
NEST. With weak low/mid-level flow, modest deep layer shear, an
increasingly capped airmass east of the CO/KS border -- any
severe weather potential is expected to be confined to eastern
Colorado between 6-10 pm MDT. Loss of insolation and an
increasingly hostile thermodynamic environment with eastern extent
will induce a weakening trend thereafter -- though one or several
MCVs emanating from upstream convection may be sufficient for
activity to persist into western KS late this evening and tonight,
where locally heavy rainfall will remain a possibility.
.LONG TERM...(Friday through Thursday)
Issued at 1255 PM MDT Thu Aug 1 2019
At the start of the period, an upper ridge spans the western half
of the country with its high centered over New Mexico. The tri-
state region remains under northwest flow on the eastern side of
the ridge.
A surface low persists to the east of the area on Friday as the
upper ridge regresses, with the anticyclone now centering over the
Four Corners. The disturbance from the previous day continues to
rotate around the ridge on its eastern side, generating shower and
thunderstorm chances in the morning (mainly for the eastern part
of the region). With these chances will come increased cloud
cover. There will likely be a lull in precipitation midday
followed by an additional opportunity for showers and storms in
the afternoon and evening behind the low as daytime heating
occurs. No severe weather is anticipated at this time.
Despite the potential for a few showers lingering into Saturday
morning to the east, dry weather is anticipated during the weekend
as surface high pressure slides over the region. The upper ridge
prevails over the southwestern portion of the CONUS through
Thursday with little change to the pattern. North to northwest
flow continues aloft next week as multiple shortwaves move through
the periphery of the ridge. This results in daily opportunities
for thunderstorms, mainly in the afternoon and evening hours,
Monday through Thursday. Widespread rainfall is not currently
anticipated.
High temperatures in the 80s are forecast Friday and Saturday,
followed by a warming trend with highs in the low 90s region-wide
by Monday. Temperatures remain in the upper 80s to low 90s
midweek. Low temperatures range in the upper 50s to upper 60s
throughout the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 549 PM MDT Thu Aug 1 2019
VFR to IFR conditions forecast for the TAFs. Main focus will be
the storm activity moving in from the west this evening/overnight.
By the time the storms move near KGLD, the threat for severe
weather should be low. Heavy rainfall and some gusty winds may
still be possible though. Confidence is lower as to what the
storm coverage will be for KMCK. Current storm motion has the
activity moving northeast by 6z, which may direct any storm
activity toward KMCK. Confidence is moderate that storms will move
over KMCK. No severe weather is expected at this time for the
site.
After the storm activity is either diminished or moved east, stratus
will move in from the northeast. KGLD should be west of the IFR
ceilings. The ceilings will gradually lift through tomorrow
morning.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...VINCENT
LONG TERM...JBH
AVIATION...JTL
Area Forecast Discussion
National Weather Service Key West FL
1023 PM EDT Thu Aug 1 2019
.DISCUSSION...
Well above normal shower and thunderstorm coverage will continue
through Saturday, then diminish on Sunday. Normal coverage is
expected from Monday through next Thursday.
.SHORT TERM...
The axis of a tropical wave was analyzed this evening along 83W.
The 00z KEY sounding observed a record-breaking (for the date)
Precipitable Water value of 2.53", indicating deep tropical
moisture. The 00z MFL sounding PW value of 2.07" is near the 80th
percentile for this date. So the abundance of shower and
thunderstorm activity this evening is not surprising. This most
concentrated area of thunderstorms originated from afternoon
convection which emerged off the north coast of Cuba. This area
continues to spread north through the Straits of Florida, with
radar showing numerous outflow boundaries upon which to focus
additional convection. The last few runs of the HRRR have been
showing numerous showers and thunderstorms for the Lower and
Middle Keys during the late evening and overnight hours,
eventually reaching the Upper Keys in the hours before sunrise.
Have given PoPs a slight nudge upward from 60 to 70 percent for
the rest of tonight.
The tropical wave will lift northward into the far eastern Gulf on
Friday. The 12z and 18z GFS ensemble means shows a bullseye of
negative MSLP anomalies near the Dry Tortugas at sunrise Friday,
lifting north to near Tampa Bay by mid-day Saturday. Over the
Keys, this movement will support a deepening and strengthening of
southerly flow through at least Friday night. PW values will
remain well over 2", and numerous outflow boundaries will act to
focus convection. With southerly flow peaking on Friday night,
this should also spread PM Cuban convection north across the
Straits, possibly reaching the Keys later Friday night.
Surface pressures rise modestly over the Keys later Saturday,
with the more unsettled weather starting to lift off to our
north. On Sunday, the subtropical ridge axis over the Atlantic
will start to expand across the Keys and South Florida. The air
mass will remain quite moist, but this evolution of the pattern
should provide a transition day during which our shower and
thunderstorm coverage starts to diminish back in the direction of
climatology. As we move from July into August, the climatological
12-hour PoP at Key West rises from near 25 percent to near 30
percent.
&&
.MARINE...
The main risk to mariners through at least Saturday will be an
abundance of showers and thunderstorms. Therefore, winds will
ultimately be gusty and erratic at times under the influence of
numerous convective outflow boundaries.
In the broader picture, prevailing moderate easterly breezes this
evening will become more southerly on Friday and Friday night, as
a weak low center drifts north from near the Dry Tortugas on
Friday morning to near Tampa Bay by mid-day Saturday.
Ridging will reestablish itself across the Florida Peninsula
through the first half of next week, resulting in a return to
gentle east to southeast breezes and scattered convection.
&&
.COASTAL FLOODING...
Tides have been running higher than normal over the past couple of
days, with anomalies around 3/4 of a foot above the astronomical
predictions. Thursday morning`s higher high tide topped at 3.03
ft at 10:48 am at the Key West Tide Gauge. In addition, a Key West
meteorologist observed a number of low lying streets and parking
lots under water around that time. Coastal Flood Statements will
likely be required daily through at least Saturday and possibly
Sunday, with the peaks occurring during high tide from the late
morning into early afternoon.
&&
.AVIATION...
VFR conditions will prevail at both EYW and MTH terminals. Sub VFR
conditions may occur for brief periods during the night and early
morning hours as scattered showers and isolated thunderstorms move
through the area. Winds east to east southeast at 10 knots.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...Haner
Aviation/Nowcasts....SDR
Data Collection......DR
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Area Forecast Discussion
National Weather Service Pueblo CO
636 PM MDT Thu Aug 1 2019
.UPDATE...
Issued at 633 PM MDT Thu Aug 1 2019
Updated forecast products based on current radar trends and HRRR
guidance. Best chance of pops will be greater EL Paso county
region next hour or so and northeast section of SE CO plains this
evening. Mtns will also continue to be showery.
&&
.SHORT TERM...(This evening through Friday)
Issued at 341 PM MDT Thu Aug 1 2019
A shortwave trough and its associated cold front will continue to
impact the region this evening. The shortwave trough continue
scattered to numerous thunderstorms over the mountains and over the
Plains, but the main severe risk will be over norther El Paso County
and Kiowa county. What is anticipated to occur is that thunderstorms
develop over the Rampart Range and the Palmer Divide and will
propagate into a more favorable environment for thunderstorm
development, then turn into a line of thunderstorms that will spread
across eastern Colorado. The CAPE values over northern El Paso
County are around 1000 J/kg with 0-6km bulk shear values around 30
kts. The main impacts will be hail around 1 inch, wind gusts up to
60 mph, locally heavy rain, and frequent cloud to ground lightning.
The main convective complex is expected to leave WFO Pueblo`s
forecast region, only to return later tonight over Kiowa County. By
that time, the line of thunderstorms will be mature and the main
risk will be gusty outflow thunderstorm winds, with magnitudes up to
70 mph. There is the potential for flash flooding over the Spring,
Junkins, and Hayden Pass burn scars since mountain thunderstorms are
expected. Thunderstorms will dissipate by around midnight, leaving
dry conditions during the overnight hours over the majority of the
area. There may be some lingering showers and thunderstorms over the
eastern San Juans during the overnight hours, and low clouds are
anticipated over the eastern plains.
Predominantly northerly flow will be in place over the region
tomorrow afternoon over the eastern plains, which takes away from
the normal upslope component of diurnal heating, so thunderstorms
are not anticipated to be as frequent tomorrow afternoon. The
southern Sangre de Cristo Mountains appear to be the QPF hot spot
for tomorrow afternoon, since the northerly component winds are
pointed up the slopes of the mountains. The plains seem to be too
stable for thunderstorm development tomorrow afternoon. the main
flash flooding risk will be over the Spring burn scar.
High temperatures tomorrow will cool off due to the cold front
passage, so expect temperatures in the low 90s over the plains, the
low 80s over the mountain valleys and the 50s to 70s over the
mountains.
.LONG TERM...(Friday night through Thursday)
Issued at 341 PM MDT Thu Aug 1 2019
Seeing the monsoonal moisture in full swing through the medium range period
leading to a healthy dose of diurnally driven showers and storms,
mostly Front Range westward early next week.
Mid-level ridging is expected to drift towards the west a bit this
weekend pushing the better chances for showers and storms into the
High Country and not much farther east into the plains. As the
high pressure then begins to drift more to our south and an
approaching mid-level trough enters from the north we should see a
quick uptick in monsoonal moisture and more widespread showers and
storms by late in the period. Highs through the week are expected
to be in the 90s across the plains and upper 70s to mid 80s in the
high valleys.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 341 PM MDT Thu Aug 1 2019
VFR conditions are anticipated over KALS, KCOS, and KPUB throughout
the forecast period. Northerly winds are expected after after a cold
front passes by this evening. Low clouds will form during the
overnight hours over KCOS and KPUB, but they aren`t expected to be
low enough to lower flight categories.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HODANISH
SHORT TERM...SKELLY
LONG TERM...HEAVENER
AVIATION...SKELLY
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
812 PM EDT Thu Aug 1 2019
.UPDATE...
Convection winding down across the region, but other thunderstorms
and light rain are moving north across the eastern half of the
Florida peninsula at this time. Most of this rain will stay out
of our area and/or weaken as it moves into eastern Polk and Sumter
counties over the next few hours since the atmosphere has already
been pretty well worked over from the earlier convection. Then
for the remainder of the night skies will be partly to mostly
cloudy and we`ll begin to see a few more showers and possibly a
thunderstorm move northeast into the region as the deep moisture
associated with the tropical wave move northwestward. This
moisture will overspread the entire area Friday leading to
abundant clouds and numerous showers and scattered thunderstorms.
Overall the present forecast looks on track and only some slight
adjustments to current conditions needed.
&&
.AVIATION...
Convection will continue to wind down this evening, but not
completely go away overnight. Then during Friday more showers and
thunderstorms will move into the region and become numerous in
the afternoon and these could cause some MVFR/local IFR conditions
along with gusty winds up to around 30 knots. Otherwise VFR
conditions are expected with northeast to east winds at 4-7 knots
tonight becoming east to southeast at 5 to 10 knots Friday
morning.
&&
.MARINE...
Main concern for the next couple of days will be the potential
for numerous showers and thunderstorms as a weak area of low
pressure is expected to develop in the southeast Gulf of Mexico
later tonight through Friday. This low will enhance the amount of
convection over the eastern Gulf waters and increase the easterly
winds to near 15 knots at times. Winds shift to the southwest to
west over the weekend as this weak low pressure shifts
northeastward back into the Atlantic Ocean.
&&
.Prev Discussion... /issued 1152 AM EDT Thu Aug 1 2019/
SYNOPSIS...
16Z water vapor and H4 RAP analysis showing a complex mid/upper
level pattern evolving over the Florida peninsula/eastern Gulf.
The region sits within a zone of mid/upper level SW flow between a
well-defined upper low spinning over the north-central Gulf of
Mexico and a large ridge of the eastern Atlantic to the east and
northeast of Florida. To complicate matters, a lower to middle
level disturbance is currently located over the Bahamas/Florida
Straits/south Florida that is slowly rounding the base of the
upper ridge. The unseasonably deep trough into the central Gulf
and this migrating disturbance will prevent a typical sea-breeze
convection type pattern for the next couple of days. Therefore,
the rainfall pattern will be more "messy"...with showers/storms
being rather numerous, but with a less defined spatial/temporal
pattern. However, the potential for heavy rainfall is certainly
there, especially south of the I-4 corridor, and this is a concern
given the saturated state of soils and elevated river levels
across much of the region. The greatest coverage of rain and
potential for localized flooding will be Friday, so will be
monitoring today`s thunderstorm activity and where the heaviest
rainfall totals occur in anticipation of potential flood watches.
SHORT TERM (Rest of Today through Friday)...
As mentioned in the synopsis...the patten the next 48 to 72
hours will not be one characteristic of "summer" in Florida. The
normal pattern dominated by sea breeze / synoptic flow interaction
to produce scattered thunderstorms will be overwhelmed by larger
scale processes and result in a broader temporal and spatial
pattern of numerous shower/storms. Basically rain chances will
be high for passing bands of showers, although attempting to put
much detail into the forecast for exactly where the forcing
mechanisms will be located is tough to do. Essentially, large
scale processes to promote lift and resulting convection will be
increasing across the region through the rest of today, along with
precipitable water values continuing to rise. PW values are
forecasts by many of the global guidance members to exceed 2.25"
on Friday, as deep moisture is advected northward within the large
scale flow. In addition, the weak disturbance approaching from the
Bahamas/Florida straits is likely to result in a weak area of low
pressure in the SE Gulf by Friday morning. Additional forcing for
ascent on the north/east side of this low is likely to make
Friday a rather wet day...potential for all of the region, but
most likely for areas along and south of the I-4 corridor. The
potential for widespread heavy rainfall amounts 1-2"+ will
certainly be higher to the south of the I-4 corridor based on the
current forecast synoptic setup.
LONG TERM...
Large scale forcing will continue to be an impact on the region
from the deep troughing in the Gulf into Saturday. However, the
weak low in the SW Gulf is expected to quickly eject northward
back into the Atlantic. This process will shift our winds out of
the southwest. With the southwest winds, the greatest rain chances
during the morning will be along the west coast...with most of the
rainfall shifting well inland by later in the day. Sunday at this
point is looking like a very similar day in terms of overall
weather impacts and pattern, although the upper trough will show
signs of deamplifying.
The early to middle portion of the upcoming work week looks to
return the forecast to one more typical for early August, with the
subtropical ridge back into control of the area...and the forecast
dominated by mainly afternoon and evening scattered storms.
FIRE WEATHER...
Abundant moisture and high rain chances will prevent any
significant fire weather concerns through the upcoming weekend.
No significant visibility impacts are expected due to fog or smoke
through the upcoming weekend.
&&
.Preliminary Point Temps/PoPs...
TPA 75 86 74 89 / 20 80 50 50
FMY 75 86 75 89 / 30 80 50 60
GIF 75 86 73 90 / 30 80 50 70
SRQ 75 87 73 89 / 20 80 50 60
BKV 73 86 72 89 / 40 80 50 60
SPG 75 87 74 89 / 20 80 50 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...Close
PREV DISCUSSION...Mroczka
UPPER AIR...Fleming
DECISION SUPPORT...Hubbard