Alert archive / Iowa / Flash Flood Watches in 2017

Flash Flood Watch 2, NWS Omaha, NE

July 26, 2017Nemaha County, Richardson County, Nebraska; Fremont County, Montgomery County, Page County, Iowa

NWS Omaha, NE issued this flash flood watch at Jul 26, 2017, 4:36 AM CDT for Nemaha County, Richardson County, Nebraska; Fremont County, Montgomery County, Page County, Iowa. It took effect at Jul 26, 2017, 1:00 PM CDT. It was in force for 8 hr.

The area

The counties it named.

The facts

Issued
Jul 26, 2017, 4:36 AM CDT (09:36 UTC)
In effect from
Jul 26, 2017, 1:00 PM CDT
Expired
Jul 26, 2017, 9:15 PM CDT
In force
8 hr
Issued by
NWS Omaha, NE
Flood severity
None

Counties Fremont County, IA, Montgomery County, IA, Page County, IA, Nemaha County, NE, Richardson County, NE

The radar

The Omaha radar (KOAX), 108 km from the middle of the area, began a volume at 09:39 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 9.6 hours before the alert went out and 108 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2017-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 826 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 2017-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
826 J/kg
Mixed-layer CIN
-88 J/kg
Mixed-layer LCL
2192 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
171 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 25, 10:25 PM CDTSpecial Weather StatementOAXKnox50 min
Jul 26, 2:17 AM CDTSpecial Weather StatementOAXAntelope, Boone43 min
Jul 26, 12:32 PM CDTAreal Flood AdvisoryOAXButler, Colfax, Dodge, Platte, Saunders3 hr
Jul 26, 5:15 PM CDTAreal Flood AdvisoryOAXLancaster2 hr

Nearby

Flash Flood Watches in Iowa, 2017Flash Flood Watches in Nebraska, 2017Every flash flood watch in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.