AWUS01 KWNH 081055
FFGMPD
ALZ000-MSZ000-LAZ000-ARZ000-TXZ000-081645-

Mesoscale Precipitation Discussion 0088
NWS Weather Prediction Center College Park MD
554 AM EST Fri Mar 08 2024

Areas affected...Central LA through Central MS...

Concerning...Heavy rainfall...Flash flooding possible

Valid 081055Z - 081645Z

SUMMARY...Veering upstream wind profile within broad warm
advection pattern should favor back-building development with
potential for training thunderstorms through early morning period.
Streaks of 2-4" totals and incidents of flash flooding are
considered possible

DISCUSSION...CIRA Sfc-850mb LPW analysis depicts a broad
triangular wedge of enhanced moisture across the northwestern Gulf
angled across southeast TX and western/central LA. VWP and RAP
analysis shows increasingly confluent/veering LLJ nosing across
northeast LA into west-central MS at this time, providing solid
40-45kts of WAA isentropic ascent across a flat frontal zone
across N LA into northeast MS at this time. Slow increase in
higher theta-E air (and Tds into the 70s) will continue to
encroach northeastward with broad ascent along and southeast of approaching/amplifying mid-level shortwave out of central TX.
Analysis also suggest weakening capping across this higher Theta-E
air where MLCAPE are ticking up over 1000 J/kg across southeast
TX.

GPS total PWat values have risen to 1.7" across this area and with
strong WAA/ascent and proximity to modest instability, increasing
convective activity will continue to expand at the nose of the LLJ
over the next few hours, slowly back-building into the richer/more
unstable air after 12z. Rates of 1.5"/hr should build to 1.75",
though cell motions of 30kts or greater should limit any one
particular cell resulting in significant totals. However, with
the approach of the wave, low level confluence will start to
become more unidirectional through a greater depth and favor some
upstream redevelopment/convergence. This should allow for
potential for training thunderstorms from the 12-18z time period
across central LA into central MS.

There still remain some modest uncertainty in the latitude of
convective initiation upstream, be it closer to the slowly sagging
frontal zone across E TX/NW LA or on the initial outflow
boundaries from ongoing/early developing convection across LA into
MS. Still, the potential for a streak or two of 2-4" totals may
result in a a few incidents of localized flash flooding.
Potential is ever so slightly higher across Carroll parish, LA to
Holmes to Lowndes county, MS where upper soil conditions are that
ever so slightly more saturated due to prior heavy rainfall over
the 7 days per AHPS and NASA SPoRT LIS products.

Gallina


ATTN...WFO...BMX...JAN...LCH...LIX...SHV...

ATTN...RFC...LMRFC...SERFC...WGRFC...NWC...

LAT...LON 33698951 33438859 32598837 31998885 31528993
31279084 30809322 31039420 31889377 32859176
33249101 33599036

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AWUS01 KWNH 091052
FFGMPD
SCZ000-FLZ000-GAZ000-ALZ000-091630-

Mesoscale Precipitation Discussion 0093
NWS Weather Prediction Center College Park MD
551 AM EST Sat Mar 09 2024

Areas affected...Eastern FL Panhandle...Far Southeast
AL...Southern GA...Adj Southern SC...

Concerning...Heavy rainfall...Flash flooding likely

Valid 091100Z - 091630Z

SUMMARY...Continued risk for training thunderstorms and 2-4"
totals resulting in possible flash flooding.

DISCUSSION...GOES-E 10.3um IR loop depicts a mature linear
convective complex across Southern GA with the upstream edge
across the far western portion of the FL Panhandle. In concert
with regional RADAR, VWP and observations suggest another subtle
low level wave is lifting northeast out of the Panhandle along the
slowly sagging WSW to ENE oriented front resulting in another
burst of convective development along the upwind edge. Ample deep
layer moisture remains attendant to the feature with total PWats
AoA 2" and the nose of central Gulf unstable air to feed the
linear complex with values of 1000 J/kg of MLCAPE from VPS to SW
GA. Increasing southerly flow across the Atlantic has
lifted/connected the warm frontal feature across southern GA and
nearing the Low country of SC. Given the favorable forcing a few
more hours of intense thunderstorms with rates of 1.5-2"/hr remain
likely.

Southward propagation of the line has begun enough to reduced
duration at any given location, but still may result in streaks of
2-4" totals over the next 5-6 hrs with slow reduction in
intensity/coverage as the wave lifts NE through mid-morning but
will drop in latitude further into the drier/sandier soils of the
Coastal Plain. Eventually into early/mid-morning, the LLJ speed
max will shift out of the Gulf into GA/SC and reduce overall deep
layer convergence and slowly fracture the convective line.
Clusters will likely continue to be highly efficient; however, the
coverage and duration may reduce enough for coverage of potential
areas of excessive rainfall to induce flash flooding. , However,
there is ongoing flash flooding from Walton county FL across SE AL
into south-central GA (Telfair county) where FFG values are
already being exceeded with continued hour or two of heavy
rainfall, so therefore flash flooding is considered likely.

Gallina


ATTN...WFO...CHS...FFC...JAX...TAE...

ATTN...RFC...SERFC...NWC...

LAT...LON 32788100 32158065 31348127 30618326 30238497
30378581 30818627 31518545 32248366 32778219

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AWUS01 KWNH 231331
FFGMPD
FLZ000-231630-

Mesoscale Precipitation Discussion 0109
NWS Weather Prediction Center College Park MD
930 AM EDT Sat Mar 23 2024

Areas affected...metropolitan areas of southeastern Florida

Concerning...Heavy rainfall...Flash flooding likely

Valid 231330Z - 231630Z

Summary...Areas of training convection are producing spots of 2-3
inch/hr rain rates over parts of the Everglades. This activity
will spread into populated areas of southeastern Florida soon,
prompting localized flash flooding.

Discussion...A lead convective cluster was located over Miami
currently. Upstream from that cluster, an axis of west-southwest
to east-northeast oriented storms were located over the Everglades
and just north of the Florida Keys. SPC Mesoanalysis and radar
mosaic imagery shows that the storms are in an abundantly moist,
unstable environment (2000 J/kg SBCAPE and nearly 2 inch PW
values), supporting efficient rainfall processes within the
storms. Additionally, a few of the storms are
orienting/developing parallel to flow aloft, enabling 2+ inch/hr
rain rates to develop despite relatively fast storm motions.

MRMS has already estimated a band of 2+ inch/hr rain rates over
the Everglades and areas west of the Miami metro area. On their
current trajectory, these rates should spread eastward and impact
the metro area, with sensitive/urbanized areas experiencing an
increased flash flood threat beginning in the next few minutes.
At least 1-2 hours of heavier downpours are expected, and wet
soils/antecedent conditions should also support excessive runoff
at times. Flash flooding will become likely for a few hours today.

Cook


ATTN...WFO...KEY...MFL...

ATTN...RFC...SERFC...NWC...

LAT...LON 26458097 26377980 25727937 24947991 24598117
25068198 26118179

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AWUS01 KWNH 012104
FFGMPD
ILZ000-MOZ000-OKZ000-KSZ000-020300-

Mesoscale Precipitation Discussion 0125
NWS Weather Prediction Center College Park MD
503 PM EDT Mon Apr 01 2024

Areas affected...northern OK, southeastern KS into central MO and
western IL

Concerning...Heavy rainfall...Flash flooding possible

Valid 012100Z - 020300Z

Summary...Increasing coverage of thunderstorms from the eastern
KS/OK border into MO and western IL may produce flash flooding
from 2-4 inches of rain through 03Z. Multiple rounds of storms are
expected for a few locations with rainfall rates possibly
exceeding 2 in/hr.

Discussion...Regional radar imagery at 2030Z showed a small
cluster of thunderstorms to the east of I-35 in northern
OK/southern KS, tracking toward the northeast. Rainfall was more
stratiform over central MO, but a few areas of embedded
thunderstorms with higher reflectivity values were observed to the
north of I-70 near Marshall and east of St. Joseph. These storms
were forming partially in response to an ejecting positively
tilted mid-level trough axis translating eastward across the
southern High Plains. SPC mesoanalysis data from 20Z showed a
broad swath of MLCAPE between 1000-2000 J/kg within the warm
sector of a frontal cyclone with a surface low located in far
northwestern MO, but with CIN remaining across many locations due
to a capping inversion located between 850-700 mb.

Expectations are for an increase in thunderstorm coverage across
MO later this afternoon/evening, as a result of 1) northeastward
thunderstorm translation from the OK/KS border and 2) new
development across the region as CIN continues to erode with low
to mid-level height falls moving eastward in association with the aforementioned trough over the southern High Plains. Shear
parameters are plenty supportive of organized cells with an
expected movement of individual cells off toward the northeast in
general, but with more of an eastward translation to thunderstorm
clusters, allowing for possible training of heavy rain from WSW to
ENE.

Additional thunderstorm development is anticipated over central to
northern OK around 00Z, ahead of the rapid eastward advancement of
a secondary cold front just entering the TX Panhandle at 20Z,
forecast to catch up to the dryline later this evening. The
anticipated secondary development of thunderstorms may pass over
some of the same locations that received rainfall from the ongoing
round near the eastern OK/KS border. Rainfall rates of 1-2 in/hr
are likely with localized potential for rates exceeding 2 in/hr.
The result of the two rounds of thunderstorms along with potential
for short term training within each individual round may result in
some flash flooding with 2-4 inches of rain through 03Z.

Otto

ATTN...WFO...EAX...ICT...ILX...LSX...OUN...SGF...TOP...TSA...

ATTN...RFC...ABRFC...MBRFC...NCRFC...NWC...

LAT...LON 40179256 40169085 40148986 40058912 39588904
39198958 38749028 38349107 37839249 37359403
36289690 36819746 38439578 39869410

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AWUS01 KWNH 161421
FFGMPD
MOZ000-MNZ000-IAZ000-KSZ000-NEZ000-SDZ000-161800-

Mesoscale Precipitation Discussion 0158
NWS Weather Prediction Center College Park MD
1021 AM EDT Tue Apr 16 2024

Areas affected...eastern Nebraska, southeastern South Dakota,
northeastern Kansas, northwestern Missouri, and western into
central Iowa

Concerning...Heavy rainfall...Flash flooding possible

Valid 161420Z - 161800Z

Summary...Bands of convection are resulting in prolonged rain
rates (including 2+ inch/hr rates at times) across the discussion
area. Areas/spots of flash flooding are possible through 18Z this
morning.

Discussion...Over the last hour or so, a couple of dominant
convective bands have taken on a favorable orientation for
training despite relatively fast steering flow and storm motions.
One of these bands extended from near Yankton, SD to near
Columbus, NE, with rightward-moving structured embedded and
assisting in both 1 inch/hr rain rates and 2-2.5 inch/3-hr rain
rates beneath the band. This area was continuing to ingest
surface-based parcels due to southeasterly low-level flow and near
60F dewpoints beneath very cold air aloft (-20C at 500mb),
contributing to relatively efficient rain rates. Local FFGs in
the 1.5 inch/hr range were being approached on a localized basis,
suggesting a continued flash flood risk as long as convection
remains rooted near the surface. Some cells were moving northward
toward cooler surface air, however, which may weaken storms and
lower rain rates as they drift into southeastern South Dakota.

Southeast of this area, a second band of more robust convection
extended from near Clarinda in southwest Iowa through Topeka, KS.
These cells are also training and fostering areas of nearly 2
inch/hr rain rates due to favorable orientation to south-southwest
steering flow aloft. Stronger buoyancy in this area was also
contributing to slightly stronger/deeper updrafts per satellite
imagery. These storms were also lifting northward toward a
low-level boundary and stable air across central Iowa, although
ascent/forcing aloft may sustain training cells toward the Des
Moines, IA area after 16Z or so.

Models suggest that warm advection/destabilization will develop
northward into areas of central/northwestern Iowa over time,
resulting in a broader spatial opportunity for deep, training
updrafts and heavy rain rates. Areas of 1-2 inch/hr rain rates
are expected to approach FFG thresholds over the discussion area
on at least a spotty basis through 18Z or so. The threat could
persist beyond 18Z, although model trends seem to indicate a
faster forward progression of convection (and less training)
through the afternoon hours. This scenario will be re-evaluated
for another potential MPD after 18Z.

Cook

ATTN...WFO...DMX...EAX...FSD...ICT...MPX...OAX...SGF...TOP...

ATTN...RFC...ABRFC...MBRFC...NCRFC...NWC...

LAT...LON 44399753 44339634 43329360 41849265 39539264
38389370 38069443 38039543 39329568 40479675
42379784 43669793

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AWUS01 KWNH 252235
FFGMPD
KSZ000-NEZ000-COZ000-260345-

Mesoscale Precipitation Discussion 0172
NWS Weather Prediction Center College Park MD
634 PM EDT Thu Apr 25 2024

Areas affected...Northwest Kansas...Southwest Nebraska...Northeast
Colorado...

Concerning...Heavy rainfall...Flash flooding possible

Valid 252235Z - 260345Z

SUMMARY...Increasing moisture flux convergence into convective
clusters within potentially favorable flow regime for
back-building and training rotating cells pose possible localize
flash flooding concerns particularly after 00z this evening.

DISCUSSION...22z surface analysis depicts rapidly deepening
surface low in east-central CO with well defined dry line and warm
fronts extending from a triple point near the Colorado/Kansas
border at the Cheyenne/Sherman county line. The dry line is wavy
extending southward along the state line though appears to be
short-term retreating into southeast Colorado which may provide a
pivotal development region for later training/repeating as they
move northward toward the triple point. The effective warm sector
is represented by low to mid 80s Temps over lower 60s Tds.
Strong/steep lapse rates via a strong EML above the boundary layer
suggest higher than normal evaporatimve effects especially in the
early stages of development. However, the very moist low levels
are strongly convergent while also being reinforced along the
north side of the warm front by cooler but still mid to upper 50s
Tds that may entrain into elevated updrafts that meander north of
the frontal zone. Compound this with strong rotating updrafts
will support localized isallobaric inflow/moisture flux loading
the lower updraft profile with ample moisture to develop heavy
rainfall accompanying hail generation.

GOES-E WV suite also depicts favorable left exit jet ascent for
cell evacuation and potential for cells to grow upscale into
clusters and perhaps a small complex. Cell motions within the
cluster are expected to have a northeast motion at 30-40kts but
stronger rotation, should slow to 20kts per RAP Bunker propagation
vectors. Additionally, with the approach of shortwave ridging,
backing cell motions toward a more northerly component will
support the potential for repeating/training profiles particularly
after 00z as mid-level drying reduces from earlier evaporation
into the environment. As such, cells producing 1-1.5"/hr rates
may start to encroach into the 1.5-2"/hr rates. This presents the
increasing possibility of pockets/scattered clusters of 2-3"
totals in 2-3 hour period. While the grounds have been dry,
natural FFG values would be in reach of being exceeded in
localized spots given 1hr values of 1.5-2" and 2-2.5/3hrs. So
while severe threat is currently the primary hazard, the
hydrological risk will be steady increasing through 00z and even a
very strong slow moving high influx super-cell may induce
localized flash flooding in the short-term.

Gallina

ATTN...WFO...BOU...DDC...GID...GLD...LBF...

ATTN...RFC...ABRFC...MBRFC...NWC...

LAT...LON 41159979 40979916 40289894 38930043 38480142
39010188 39510237 39990323 40730306 41020220
41080090

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AWUS01 KWNH 261023
FFGMPD
MOZ000-ARZ000-TXZ000-OKZ000-KSZ000-261530-

Mesoscale Precipitation Discussion 0175
NWS Weather Prediction Center College Park MD
622 AM EDT Fri Apr 26 2024

Areas affected...Portions of Far Northern TX...South-Central to
Northeast OK...Far Southeast KS...Far Northwest AR...Southwest MO

Concerning...Heavy rainfall...Flash flooding possible

Valid 261020Z - 261530Z

SUMMARY...Heavy showers and thunderstorms with some instances of
cell-training may result in areas of flash flooding this morning.

DISCUSSION...Radar and satellite imagery shows a broken QLCS
advancing generally east-northeast across portions of the Red
River Valley, with somewhat more disorganized activity noted
farther up to the northeast across northeast OK and southeast KS.

A shortwave trough continues to cross the region while interacting
with a moderately unstable airmass characterized by MUCAPE values
of 2000 to 2500+ J/kg, and with a persistently moist
south-southwest low-level jet of 40 to 50 kts. Given the level of
forcing and instability that is in place, the convective activity
should persist through the morning hours and may even locally
expand in coverage.

Some cell-training will be possible as the convection evolves
close to the Red River Valley and up through eastern OK over the
next few hours. Rainfall rates are expected to reach as high as
1.5 to 2 inches/hour given the level of moisture transport and
instability focusing across the region. The latest HRRR guidance
has been trending wetter and strongly supports the idea of the
convection becoming oriented more parallel to the deeper layer
southwest steering flow. The HRRR does favor some potential for
localized 3 to 5 inch rainfall totals across eastern OK going
through late this morning given the cell-training concerns. This
may result in some instances of flash flooding as a result across
this region.

The other concern this morning is also farther northeast up across
far southeast KS and into southwest MO where heavy rainfall over
the last 24 hours has led to notably moist soil conditions and
elevated streamflows at least locally. Some additional broken
clusters of convection are expected here with the arrival of the
aforementioned shortwave energy, with an additional 2 to 3 inches
of rain possible by late morning. Some instances of flash flooding
will be possible here as a result.

Orrison

ATTN...WFO...EAX...FWD...ICT...LZK...OUN...SGF...SHV...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...WGRFC...NWC...

LAT...LON 38479407 38079297 36629322 35049410 33859524
33159699 33219861 33599872 34259776 35109704
35949631 36519582 37299536 38119463

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