NWS Jackson, MS wrote its last area forecast discussion before the first event at Sep 4, 3:38 PM CST, 22 minutes earlier.
Area forecast discussion, Sep 4, 3:38 PM CST, 22 minutes before
Area Forecast Discussion
National Weather Service Jackson MS
438 PM CDT Tue Sep 4 2018
...GORDON TO BRING GUSTY WINDS, HEAVY RAIN AND TORNADOES TO PORTIONS
OF THE ARKLAMISS...
.DISCUSSION...
Tonight through Wednesday night:
Expect an active period with the main focus of the period on
Tropical Storm Gordon moving towards landfall along the northern
Gulf Coast tonight, with impacts expected tonight and through
Wednesday across the ArkLaMiss.
Tropical Storm Gordon is nearing the northern Gulf Coast this
afternoon & still continues to look somewhat lopsided due to
southerly shear impacting the storm. Overall, most of the convection
still remains to the north & east of the center of circulation & may
remain that way until landfall. National Hurricane Center is
forecasting landfall of Gordon later tonight as a a low-end Category
1 hurricane along the Mississippi Gulf Coast, with wind gusts upwards
of 75-80mph or slightly higher. The upper synoptic pattern with
mid- level ridging over the mid-Atlantic & extending westward into
the mid- Mississippi Valley favors a continued northwest track
through landfall & into tomorrow morning before a gradual slowing
of forward speed. Expect Gordon to rapidly weaken to a tropical
depression over the next 24-36 hours as it moves inland across
central Mississippi by mid- morning Wednesday & into northwest
Mississippi Delta & southeast Arkansas going into Wednesday night
& Thursday morning. The overall path of the global & CAM guidance
seems to focus from landfall through tomorrow evening right along
the Pine Belt, the Highway 45 corridor into central Mississippi &
into the northwest Delta by late Wednesday & early Thursday
morning.
Expect winds to increase tonight as Gordon makes landfall, possibly
upwards of 40-55mph in the Pine Belt to maybe upwards of 30-40mph as
it moves towards the I-20 corridor by daybreak Wednesday. As a
result of rapid weakening & small inner core of the storm, the area
of strongest winds will remain in the Pine Belt, where the Tropical
Storm Warning remains in effect. Elsewhere outside of the Tropical
Storm Warning, winds won't be as strong, mainly in the 20-30mph with
gusts upward of 30-40mph. Just be aware that any deviation eastward
or wobble in the track could result in larger change in area of
winds. HWO & graphics look good overall & no large changes were
needed to the wind.
In addition to winds, heavy rain looks to be the biggest focus. As
the system moves in with nearly 2.5 inch PWs & 340K+ 850mb Theta,
this high moisture combined with convection & convergent rain bands
will lead to high rainfall totals. Right now we will continue to
advertise 3-6 inches with locally higher amounts, but some of the
CAM guidance shows some potential for some higher amounts of 7-8+
inches, especially along the track of Gordon or any areas of
convergent or training boundaries. Right now, the Flash Flood watch
remains in effect, but only changes were to include Grenada,
Montgomery & Lauderdale Counties as well. The rainfall should be
mostly confined along that track & the southwestern extent may be
more in question. For now, kept mention of that & some of this heavy
rain potential will linger into the ArkLaMiss Delta into the
overnight hours as Gordon weakens & slows down. HREF prob. max mean
seems to be hitting on this idea of higher amounts as well. Thus,
with coordination with WPC, went with higher QPF in the forecast &
expanded the "Elevated" & Limited" areas slightly in the
HWO/graphics. Will have to keep a close eye as there might be
potential for a "Significant" to be introduced in a more confined
area if CAM & HREF suite continue to paint a higher picture of QPF.
Lastly, low-level wind shear will increase as Gordon approaches &
makes landfall overnight. Due to that, the "Marginal" Risk was
expanded northward along the Highway 82 corridor and east of the
Mississippi River. In areas along & east of the track, there seems
to be enough wind shear (i.e. bulk shear ~30-40kts @ 0-2km & 0-3km)
& increased low-level helicity for some brief tornadoes. Will have
to monitor as the overall track of Gordon will make a difference in
the westward extent into the afternoon.
Expect Gordon to weaken as it continues to trek across the ArkLaMiss
Delta & into southeast Arkansas Wednesday night. There could remain
some flash flooding & severe potential into Thursday but for now,
will keep any mention out of the HWO/graphics. Expect highest rain &
storm chances to remain confined in the Delta with scattered to
numerous rain chances elsewhere going into Thursday morning. /DC/
Thursday through next Monday:
The center of the remnants of TS Gordon will be just to the NW of
the JAN CWA by Thursday morning. Heavy rainfall could be still
ongoing in the MS Delta, NE LA, and SE Arkansas as the system
continues it's slow trek to the NW before it merges with a front
just west of the mid MS River Valley on Friday. Deep tropical
moisture will continue to exist over the region on Thursday and
Friday with PWat values exceeding 2". Diurnal type thunderstorms
will develop by each afternoon. These thunderstorms could pose a
continued flood threat for areas that receive significant amounts
of rainfall on Wednesday due to Gordon.
Although a slightly drier airmass will exist through the weekend,
diurnal thunderstorms will still be possible on Saturday and
Sunday. The front that absorbed Gordon will finally begin to
approach the region late in the weekend. Models agree on the front
stalling over the region early next week, serving as a focus for
rain and storms through the period. Rain and storms on Thursday
and Friday will help keep temperatures a few degrees below normal.
High temperatures will bounce back to closer to normal on
Saturday and Sunday before falling back below normal during early
next week due to rain and storms associated with the stalled
front. /JPM3/
&&
.AVIATION...
18Z TAF discussion:
Flight cats across the region should predominately wait until this
evening to start going downhill (sub-VFR), although some isolated
and temporary issues are possible through this afternoon (mainly
at NMM/MEI/PIB/HBG) due to passing downpours in advance of TS
Gordon in the Gulf of Mexico. The main impact from Gordon should
advance into HBG/PIB this evening and toward JAN/HKS/MEI/NMM late
tonight. Expect IFR to MVFR conditions with the worst of the
conditions due to ceilings and visibilities issues and heavy rain
with gusty east to southeast (gusting up to 30 kts at times)
possible at that point as well. Farther north, anticipate the
worst of the conditions and gusty east to southeast winds up to 25
to 30 mph will basically hold off until the daylight hours
tomorrow. Conditions will likely start to slowly improve, at least
at PIB/HBG, by late tomorrow afternoon into tomorrow evening. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 73 82 73 87 / 77 97 60 63
Meridian 73 83 73 88 / 83 86 33 58
Vicksburg 74 82 73 88 / 41 85 73 66
Hattiesburg 72 84 73 87 / 99 93 39 58
Natchez 73 84 73 86 / 44 75 62 61
Greenville 74 83 73 84 / 20 81 77 75
Greenwood 74 82 73 86 / 31 81 68 69
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Flash Flood Watch through Wednesday evening for MSZ037-043>045-
048>059-061>066-072>074.
Flash Flood Watch from Wednesday morning through Thursday
morning for MSZ018-019-025>028-034-035-040-041.
Flash Flood Watch through Thursday morning for MSZ036-042-047.
Tropical Storm Warning for MSZ072>074.
LA...Flash Flood Watch from Wednesday morning through Thursday
morning for LAZ007>009-015-016-023-025.
AR...Flash Flood Watch from Wednesday morning through Thursday
morning for ARZ074-075.
&&
DC/JPM3/BBHazardous weather outlook, Sep 4, 11:23 AM CST, 4 hours 37 minutes before
Hazardous Weather Outlook...UPDATED
National Weather Service Jackson MS
1223 PM CDT Tue Sep 4 2018
ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>041-051730-
Ashley-Chicot-Morehouse-West Carroll-East Carroll-Richland-
Madison LA-Franklin LA-Catahoula-Tensas-Concordia-Bolivar-
Sunflower-Leflore-Grenada-Carroll-Montgomery-Webster-Clay-Lowndes-
Choctaw-Oktibbeha-Washington-Humphreys-Holmes-Attala-Winston-
Noxubee-Issaquena-Sharkey-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of southeast
Arkansas, northeast Louisiana, central Mississippi, and north
central Mississippi.
.DAY ONE...The rest of Today and Tonight
The probability for widespread hazardous weather is low.
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight into Wednesday across central Mississippi and far
northeastern Louisiana.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region Wednesday
through Wednesday night.
MSZ042-044>046-051730-
Yazoo-Leake-Neshoba-Kemper-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of central
Mississippi, and east central Mississippi.
.DAY ONE...The rest of Today and Tonight
SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...Late tonight
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight.
(https://www.weather.gov/images/jan/graphicast/3.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight and into Wednesday across central Mississippi and far
northeastern Louisiana.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region tonight
through Wednesday night.
MSZ043-047>050-053-054-062-051730-
Madison MS-Warren-Hinds-Rankin-Scott-Claiborne-Copiah-Lincoln-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of central
Mississippi, south central Mississippi, southwest Mississippi,
and west central Mississippi.
.DAY ONE...The rest of Today and Tonight
SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...After midnight
NON-THUNDERSTORM WINDS
THREAT...Limited
TIMING...Late tonight
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight.
(https://www.weather.gov/images/jan/graphicast/3.png)
The threat for gusty winds will begin to move into the area late
tonight into early morning hours of Wednesday.
(https://www.weather.gov/images/jan/graphicast/2.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Gusty winds associated with Tropical Storm Gordon are expected
continuing into Wednesday. Wind gusts of 30 to 40 mph are
possible, which may result in downed trees and powerlines.
(https://www.weather.gov/images/jan/graphicast/2.png)
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight and into Wednesday across central Mississippi and far
northeastern Louisiana.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region tonight
through Wednesday night.
MSZ051-052-058-051730-
Newton-Lauderdale-Clarke-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of east central
Mississippi.
.DAY ONE...The rest of Today and Tonight
SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...After midnight
FLOODING
THREAT...Limited
TIMING...Late tonight
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight.
(https://www.weather.gov/images/jan/graphicast/3.png)
Rainfall associated with Tropical Storm Gordon may result in
localized flash flooding, particularly in low lying and urban
areas. Storm total rainfall accumulations of 1 to 3 inches are
expected, with locally higher amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight and into Wednesday across central Mississippi and far
northeastern Louisiana.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region tonight
through Wednesday night.
MSZ059>061-051730-
Jefferson-Adams-Franklin MS-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of southwest
Mississippi.
.DAY ONE...The rest of Today and Tonight
NON-THUNDERSTORM WINDS
THREAT...Limited
TIMING...Late tonight
The threat for gusty winds will begin to move into the area late
tonight into early morning hours of Wednesday.
(https://www.weather.gov/images/jan/graphicast/2.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Gusty winds associated with Tropical Storm Gordon are expected
continuing into Wednesday. Wind gusts of 30 to 40 mph are
possible, which may result in downed trees and powerlines.
(https://www.weather.gov/images/jan/graphicast/2.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations is not expected through next Monday.
MSZ055>057-063>065-051730-
Simpson-Smith-Jasper-Lawrence-Jefferson Davis-Covington-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of central
Mississippi, east central Mississippi, south central Mississippi,
and southeast Mississippi.
.DAY ONE...The rest of Today and Tonight
SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...After midnight
FLOODING
THREAT...Limited
TIMING...Late this evening into tonight
NON-THUNDERSTORM WINDS
THREAT...Limited
TIMING...Late this evening into tonight
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight.
(https://www.weather.gov/images/jan/graphicast/3.png)
Rainfall beginning late this evening and continuing into
Wednesday associated with Tropical Storm Gordon is expected to
result in flash flooding. Storm total rainfall accumulations of 3
to 6 inches are expected, with locally higher amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Gusty winds associated with Tropical Storm Gordon are expected
beginning late this evening and into tonight. Wind gusts of 30 to
40 mph are possible, which may result in downed trees and
powerlines.
(https://www.weather.gov/images/jan/graphicast/2.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Gusty winds associated with Tropical Storm Gordon are expected
continuing into Wednesday. Wind gusts of 30 to 40 mph are
possible, which may result in downed trees and powerlines.
(https://www.weather.gov/images/jan/graphicast/2.png)
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight and into Wednesday across central Mississippi and far
northeastern Louisiana.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region tonight
through Wednesday night.
MSZ066-051730-
Jones-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of southeast
Mississippi.
.DAY ONE...The rest of Today and Tonight
SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...After midnight
FLOODING
THREAT...Elevated
TIMING...Late this evening into tonight
NON-THUNDERSTORM WINDS
THREAT...Limited
TIMING...Late this evening into tonight
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight.
(https://www.weather.gov/images/jan/graphicast/3.png)
Rainfall beginning late this evening and continuing into
Wednesday associated with Tropical Storm Gordon is expected to
result in flash flooding. Storm total rainfall accumulations of 3
to 6 inches are expected, with locally higher amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Gusty winds associated with Tropical Storm Gordon are expected
beginning late this evening and into tonight. Wind gusts of 30 to
40 mph are possible, which may result in downed trees and
powerlines.
(https://www.weather.gov/images/jan/graphicast/2.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Rainfall on Wednesday and Wednesday night associated with
Tropical Storm Gordon is expected to result in flash flooding,
particularly across the ArklaMiss Delta. Storm total rainfall
accumulations of 3 to 6 inches are expected, with locally higher
amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Gusty winds associated with Tropical Storm Gordon are expected
continuing into Wednesday. Wind gusts of 30 to 40 mph are
possible, which may result in downed trees and powerlines.
(https://www.weather.gov/images/jan/graphicast/2.png)
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight and into Wednesday across central Mississippi and far
northeastern Louisiana.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region tonight
through Wednesday night.
MSZ072>074-051730-
Marion-Lamar-Forrest-
1223 PM CDT Tue Sep 4 2018
This hazardous weather outlook is for portions of south central
Mississippi, and southeast Mississippi.
.DAY ONE...The rest of Today and Tonight
SEVERE THUNDERSTORMS
THREAT...Marginal
TIMING...After midnight
FLOODING
THREAT...Elevated
TIMING...Late this evening into tonight
NON-THUNDERSTORM WINDS
THREAT...Elevated
TIMING...Late this evening into tonight
As Tropical Storm Gordon moves across the region, brief tornadoes
and damaging wind gusts in rain bands are possible beginning late
tonight.
(https://www.weather.gov/images/jan/graphicast/3.png)
Rainfall beginning late this evening and continuing into
Wednesday associated with Tropical Storm Gordon is expected to
result in flash flooding. Storm total rainfall accumulations of 3
to 6 inches are expected, with locally higher amounts possible.
(https://www.weather.gov/images/jan/graphicast/1.png)
Strong wind associated with Tropical Storm Gordon is expected
beginning late this evening. Wind gusts of 40 to 55 mph are
possible, which may result in numerous downed trees and
powerlines, some damage to roofs and homes, and some blocked
roadways.
(https://www.weather.gov/images/jan/graphicast/2.png)
.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Flash flooding concerns will continue into the daytime Wednesday.
(https://www.weather.gov/images/jan/graphicast/1.png)
The threat for tropical storm winds will continue into the
daytime Wednesday.
(https://www.weather.gov/images/jan/graphicast/2.png)
The threat for brief tornadoes and damaging wind gusts will
continue into the daytime Wednesday.
(https://www.weather.gov/images/jan/graphicast/3.png)
.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations may be needed for portions of the region tonight
through Wednesday night.
23
&&
...HAZARD LEGEND...
*SEVERE THUNDERSTORMS*
High...Significant severe thunderstorms are expected.
Moderate...Severe storms expected with significant
severe weather possible.
Enhanced...Severe storms expected.
Slight...Severe storms possible.
Marginal...Isolated severe storms possible.
*NON-THUNDERSTORM WINDS*
Extreme...Sustained winds 50 mph or greater or wind gusts 65 mph
or greater.
Significant...Sustained winds 40-49 mph or wind gusts 58-64 mph.
Elevated...Sustained winds 30-39 mph or wind gusts 45-57 mph.
Limited...Sustained winds 20-29 mph or wind gusts 30 to 44 mph.
*FLOODING*
Extreme...Confident in significant flooding.
Significant...Significant flooding possible.
Elevated...Confident in flooding.
Limited...Flooding possible.
...USEFUL WEATHER WEB PAGES (URLS)...
NWS JAN Home page...
https://www.weather.gov/jan
Stay Aware, Stay Safe NWS JAN Briefing Page...
https://www.weather.gov/jan/safe
Latest Weather Briefing...
https://www.weather.gov/jan/weather_briefing
Tropical page...
https://www.weather.gov/jan/srh/tropical?office=jan
National Hurricane Center Home Page...
https://www.nhc.noaa.gov/
Find NWS JAN on Facebook...
https://www.facebook.com/NWSJacksonMS
Follow NWS JAN on Twitter...
@NWSJacksonMS
Follow NWS JAN on Youtube...
https://www.youtube.com/user/NWSJacksonMiss
...ADDITIONAL URLS FOR SEVERE WEATHER ISSUES...
Storm Prediction Center (SPC)...
https://www.spc.noaa.gov/
Meso Analysis...
https://www.spc.noaa.gov/exper/mesoanalysis/
Day 1 through 3 Outlooks...
https://www.spc.noaa.gov/products/outlook/
Storm Reports...
https://www.spc.noaa.gov/climo/online/
...ADDITIONAL URLS FOR FLOODING ISSUES...
Current Watches and Warnings...
https://www.weather.gov/jan/safe_HeavyRain
Observed Precipitation Images...
https://www.weather.gov/jan/precipmaps
River Forecast Center...
https://www.weather.gov/lmrfc/
Significant River Flood Outlook...
https://www.wpc.ncep.noaa.gov/nationalfloodoutlook/index.html
Day 1 through 3 Excessive Rainfall...
https://www.wpc.ncep.noaa.gov/qpf/excess_rain.shtml
Excessive Rainfall Discussion...
https://www.wpc.ncep.noaa.gov/discussions/qpferd.html
Day 1 through 7 QPF...
https://www.wpc.ncep.noaa.gov/qpf/qpf2.shtml
QPF Discussion...
https://www.wpc.ncep.noaa.gov/discussions/qpfpfd.html