Alert archive / Delaware / Flash Flood Warnings in 2018
Flash Flood Warning 91, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 1, 2018, 5:36 AM EDT for Sussex County, Delaware. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Sep 1, 2018, 5:36 AM EDT (09:36 UTC)
- Expired
- Sep 1, 2018, 9:30 AM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
County Sussex County, DE
The nearest sounding before it
Wallops Is Stn, VA (KWAL), launched 00:00Z, 9.6 hours before the alert went out and 96 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.
- Mixed-layer CAPE
- 2306 J/kg
- Mixed-layer CIN
- -1 J/kg
- Mixed-layer LCL
- 574 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 48 m²/s²
- 0-3 km storm-relative helicity
- 126 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.9
The text
As transmitted.
644 WGUS51 KPHI 010936 FFWPHI DEC005-011330- /O.NEW.KPHI.FF.W.0091.180901T0936Z-180901T1330Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED Flash Flood Warning National Weather Service Mount Holly NJ 536 AM EDT SAT SEP 1 2018 The National Weather Service in Mount Holly NJ has issued a * Flash Flood Warning for... Central Sussex County in southern Delaware... * Until 930 AM EDT. * At 535 AM EDT, Doppler radar indicated heavy rain across the warned area. Up to two inches of rain have already fallen. Flash flooding is expected to begin shortly in the areas of heaviest rain. * Some locations that could experience flooding include... Milton and Ellendale. Additional rainfall amounts of one to two inches are possible in the warned area. This is falling in an area that already has saturated ground from storms on Friday, so any additional rain will quickly become runoff. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around...don't drown when encountering flooded roads. Most flood deaths occur in vehicles. && LAT...LON 3884 7524 3870 7521 3873 7545 3884 7542 $$ SFJ
2 follow-up statements
823 WGUS71 KPHI 011059 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 659 AM EDT SAT SEP 1 2018 DEC005-011330- /O.CON.KPHI.FF.W.0091.000000T0000Z-180901T1330Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Sussex DE- 659 AM EDT SAT SEP 1 2018 ...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 AM EDT FOR CENTRAL SUSSEX COUNTY... At 658 AM EDT, Doppler radar indicated heavy rain across the warned area. Up to three inches of rain have fallen on already saturated ground. Flash flooding is expected to begin shortly. Although the heaviest rain has ended, it will take time for the runoff to recede. Some locations that could experience flooding include... Milton and Ellendale. PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around...don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Excessive runoff from heavy rainfall will cause flooding of small creeks and streams, country roads, farmland, and other low lying spots. && LAT...LON 3884 7524 3870 7521 3873 7545 3884 7542 $$ SFJ
247 WGUS71 KPHI 011335 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 935 AM EDT SAT SEP 1 2018 DEC005-011345- /O.EXP.KPHI.FF.W.0091.000000T0000Z-180901T1330Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Sussex DE- 935 AM EDT SAT SEP 1 2018 ...THE FLASH FLOOD WARNING FOR CENTRAL SUSSEX COUNTY HAS EXPIRED... The heavy rain has ended. Flooding is no longer expected to pose a threat. Please continue to heed any remaining road closures. LAT...LON 3884 7524 3870 7521 3873 7545 3884 7542 $$ CMS
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 31, 8:28 PM EDT | Areal Flood Warning | PHI | Sussex | 3 hr |
| Aug 31, 8:55 PM EDT | Areal Flood Warning | PHI | New Castle | 3 hr |
| Sep 1, 4:30 AM EDT | Areal Flood Advisory | PHI | Sussex | 4 hr |
| Sep 1, 4:03 PM EDT | Areal Flood Advisory | PHI | Sussex | 3 hr |
Nearby
Flash Flood Warnings in Delaware, 2018Every flash flood warning in 2018
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.