Alert archive / North Carolina / Flash Flood Watches in 2020

Flash Flood Watch 5, NWS Raleigh, NC

August 15, 202016 counties in North Carolina

NWS Raleigh, NC issued this flash flood watch at Aug 15, 2020, 3:56 AM EDT for 16 counties in North Carolina. It took effect at Aug 15, 2020, 5:00 AM EDT. It was in force for 17 hr.

The area

The counties it named.

The facts

Issued
Aug 15, 2020, 3:56 AM EDT (07:56 UTC)
In effect from
Aug 15, 2020, 5:00 AM EDT
Expired
Aug 15, 2020, 9:53 PM EDT
In force
17 hr
Issued by
NWS Raleigh, NC
Flood severity
None

Counties Alamance County, NC, Chatham County, NC, Davidson County, NC, Durham County, NC, Forsyth County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Halifax County, NC, Nash County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Vance County, NC, Wake County, NC, Warren County, NC

The radar

The Raleigh/Durham radar (KRAX), 62 km from the middle of the area, began a volume at 08:00 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 7.9 hours before the alert went out and 84 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, Greensboro/Hi Pt, NC at 00:00Z on 2020-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 754 joules per kilogram.LCLEL10008507005003002001001 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, Greensboro/Hi Pt, NC at 00:00Z on 2020-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 square meters per square second.1939Sfc1 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
754 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
787 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Raleigh, NC wrote its last area forecast discussion before this flash flood watch went out at Aug 15, 3:48 AM EDT, 8 minutes earlier.

Area forecast discussion, Aug 15, 3:48 AM EDT, 8 minutes before
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Hazardous weather outlook, Aug 14, 6:33 AM EDT, 21 hours 23 minutes before
Hazardous Weather Outlook
National Weather Service Raleigh NC
633 AM EDT Fri Aug 14 2020

NCZ007>011-021>028-038>043-073>078-083>086-088-089-151200-
Person-Granville-Vance-Warren-Halifax-Forsyth-Guilford-Alamance-
Orange-Durham-Franklin-Nash-Edgecombe-Davidson-Randolph-Chatham-Wake-
Johnston-Wilson-Stanly-Montgomery-Moore-Lee-Harnett-Wayne-Anson-
Richmond-Scotland-Hoke-Cumberland-Sampson-
633 AM EDT Fri Aug 14 2020

This Hazardous Weather Outlook is for central North Carolina.

.DAY ONE...Today and tonight.

Slow-moving thunderstorms will produce locally heavy rain and a risk
of flooding this afternoon and tonight.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Thunderstorms on Saturday will be capable of producing both
localized flooding and strong wind gusts up to 45 mph.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Local storm report, Aug 14, 10:23 PM EDT, 5 hours 33 minutes before
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Local storm report, Aug 14, 10:25 PM EDT, 5 hours 31 minutes before
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Local storm report, Aug 14, 10:26 PM EDT, 5 hours 30 minutes before
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Local storm report, Aug 14, 10:28 PM EDT, 5 hours 28 minutes before
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The office that day

Everything else NWS Raleigh, NC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 14, 8:48 PM EDTAreal Flood AdvisoryRAHDurham, Franklin, Johnston, Nash, Wake117 min
Aug 15, 1:40 PM EDTSpecial Weather StatementRAHForsyth65 min
Aug 15, 2:13 PM EDTSpecial Weather StatementRAHWilson47 min
Aug 15, 2:16 PM EDTAreal Flood AdvisoryRAHForsyth, Guilford3 hr
Aug 15, 2:28 PM EDTSpecial Weather StatementRAHWarren62 min
Aug 15, 2:32 PM EDTSpecial Weather StatementRAHWilson58 min
Aug 15, 2:38 PM EDTAreal Flood AdvisoryRAHJohnston, Wilson55 min
Aug 15, 3:03 PM EDTSpecial Weather StatementRAHDavidson42 min
Aug 15, 3:29 PM EDTSpecial Weather StatementRAHHalifax61 min
Aug 15, 3:44 PM EDTSpecial Weather StatementRAHFranklin61 min
Aug 15, 4:14 PM EDTAreal Flood AdvisoryRAHFranklin, Wake3 hr
Aug 15, 4:32 PM EDTFlash Flood Warning Considerable damage threatRAHDurham, Franklin, Wake3 hr
Aug 15, 4:32 PM EDTSpecial Weather StatementRAHOrange58 min
Aug 15, 5:03 PM EDTSpecial Weather StatementRAHWayne57 min
Aug 15, 5:27 PM EDTSpecial Weather StatementRAHWake63 min
Aug 15, 6:14 PM EDTAreal Flood AdvisoryRAHWake3 hr
Aug 15, 6:45 PM EDTSpecial Weather StatementRAHWake60 min
Aug 15, 7:19 PM EDTFlash Flood Warning Considerable damage threatRAHHarnett9 hr

Nearby

Flash Flood Watches in North Carolina, 2020Every flash flood watch in 2020

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.