National Weather Service United States Department of Commerce

Back-to-Back Pacific Storms to Impact the West Coast; Heavy Snow in the Central Appalachians

Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >

Overview

A strong upper-level trough approached the Mid-Atlantic during the afternoon of 26 April 2019. An attendant cold front swept through the area during the afternoon and evening.  A line of intense storms developed along the front in the Appalachians and progressed eastward through the area between 3 and 8 pm.  Embedded within the line were multiple bowing segments, indicative of strong wind gusts reaching the surface.  Wind damage occurred in several locations in southeast Pennsylvania, southwest New Jersey, and Delmarva in association with the line of storms.  The most severe damage occurred in the Narberth (PA) and Cherry Hill (NJ) areas, where numerous instances of downed trees and roof damage were reported.  As the line approached the cooler ocean waters during the mid-evening hours, the storms quickly weakened (aided by the loss of daytime heating).

 

 

 

 

Image
KDIX Radar Loop during the afternoon/evening of 26 April 2019.

Meteorological Environment/Setup

Synoptic Overview at 12z 26 April 2019 (courtesy of SPC)

Environment Environment Environment
Figure 1: 250-mb analysis Figure 2: 300-mb analysis Figure 3: 500-mb analysis
 
Environment Environment Environment
Figure 4: 700-mb analysis Figure 5: 850-mb analysis Figure 6: 925-mb analysis

Synoptic Overview at 00z 27 April 2019 (courtesy of SPC)

Environment Environment Environment
Figure 7: 250-mb analysis Figure 8: 300-mb analysis Figure 9: 500-mb analysis
 
Environment Environment Environment
Figure 10: 700-mb analysis Figure 11: 850-mb analysis Figure 12: 925-mb analysis
 

Surface Maps (courtesy of WPC)

Environment Environment Environment
Figure 13: 15z surface map Figure 14: 18z surface map Figure 15: 21z surface map
 
Environment Environment Environment
Figure 16: 00z surface map Figure 17: 03z surface map Figure 18: 06z surface map

Observed Soundings
Environment Environment Environment
Figure 19: 12z Upton, NY sounding Figure 20: 12z Sterling, VA sounding Figure 21: 12z Wallops Island, VA sounding
Environment Environment Environment
Figure 22: 00z Upton, NY sounding Figure 23: 00z Sterling, VA sounding Figure 24: 00z Wallops Island, VA sounding

Preliminary Storm Reports

prelimreports prelimreports prelimreports
Figure 1: National Preliminary Reports 12z 26 April 2019 to 12z 27 April 2019 Figure 2: Zoomed Preliminary Reports for the same period. Figure 3: Prelim Reports vs. 1630z SPC Convective Outlook

Preliminary Local Storm Reports

 

NWUS51 KPHI 272029
LSRPHI

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
429 PM EDT SAT APR 27 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0711 PM     MARINE TSTM WIND 1 E BARNEGAT LIGHT      39.76N 74.09W
04/26/2019  M46 MPH          ANZ451             NJ   MESONET          

            THE BARNEGAT ISLAND LIGHT WXFLOW SENSOR 
            REPORTED A GUST OF 40 KNOTS. 

0624 PM     MARINE TSTM WIND STONE HARBOR            39.06N 74.77W
04/26/2019  M46 MPH          ANZ453             NJ   MESONET          

            STONE HARBOR HADS SENSOR MEASURED A GUST OF 
            40 KNOTS. 

0619 PM     TSTM WND DMG     COLUMBUS                40.08N 74.72W
04/26/2019                   BURLINGTON         NJ   PUBLIC           

            SMALL TREES AND POWER LINES DOWN. IMAGES 
            SHARED WITH US ON SOCIAL MEDIA. TIME 
            ESTIMATED FROM RADAR. 

0617 PM     TSTM WND DMG     1 W PROSPECT PARK       40.24N 74.79W
04/26/2019                   MERCER             NJ   TRAINED SPOTTER  

            LARGE TREE DOWN IN PARK. TIME ESTIMATED FROM 
            RADAR. 

0612 PM     TSTM WND DMG     1 NNE VILLAS            39.04N 74.93W
04/26/2019                   CAPE MAY           NJ   TRAINED SPOTTER  

            TREE SPLIT AND INTO WIRES ON BAYSHORE ROAD. 
            TIME ESTIMATED FROM RADAR. 

0610 PM     TSTM WND DMG     RANCOCAS                40.01N 74.87W
04/26/2019                   BURLINGTON         NJ   PUBLIC           

            TREES AND LARGE LIMBS REPORTED TO BE DOWN 
            AND TO HAVE KNOCKED OUT POWER LINES. TIME 
            ESTIMATED FROM RADAR. 

0551 PM     TSTM WND DMG     ELLISBURG               39.92N 75.00W
04/26/2019                   CAMDEN             NJ   NEWSPAPER        

            REPORTS OF WIND DAMAGE IN THE ELLISBURG 
            AREA. TREES WERE UPROOTED AND CAUSED 
            PROPERTY DAMAGE AT ONE RESIDENCE ON MAINE 
            AVENUE. TIME ESTIMATED FROM RADAR. 

0550 PM     TSTM WND DMG     2 SE WARMINSTER TWP.    40.18N 75.06W
04/26/2019                   BUCKS              PA   DEPT OF HIGHWAYS 

            DOWNED TREE AND WIRES ON PA-132 EASTBOUND AT 
            DAVISVILLE ROAD. ONE LANE IS BLOCKED. TIME 
            ESTIMATED FROM RADAR. 

0549 PM     TSTM WND DMG     WARMINSTER              40.21N 75.10W
04/26/2019                   BUCKS              PA   PUBLIC           

            SEVERAL TREES AND A FEW POWER LINES DOWN IN 
            WARMINSTER. TIME ESTIMATED FROM RADAR. 

0549 PM     TSTM WND DMG     1 NE HADDONFIELD        39.91N 75.01W
04/26/2019                   CAMDEN             NJ   PUBLIC           

            SEVERAL REPORTS OF WIND DAMAGE BETWEEN 
            CHERRY HILL AND HADDONFIELD, INCLUDING AT 
            THE CONNECT CHURCH, ON KNOLLWOOD DRIVE, ON 
            CORNELL AVENUE, AND ON MASSACHUSETTS AVENUE. 
            NUMEROUS TREES AND POWER LINES DOWN, SEVERAL 
            OF WHICH RESULTED IN PROPERTY DAMAGE. 

0545 PM     TSTM WND DMG     ROCKLEDGE               40.08N 75.09W
04/26/2019                   MONTGOMERY         PA   FIRE DEPT/RESCUE 

            DOWNED TREE NEAR THE INTERSECTION OF 
            MONTGOMERY AVENUE AND CENTRAL AVENUE. TIME 
            ESTIMATED FROM RADAR. 

0545 PM     TSTM WND DMG     RICHLANDTOWN            40.47N 75.32W
04/26/2019                   BUCKS              PA   PUBLIC           

            TREES DOWN. TIME ESTIMATED FROM RADAR. 

0545 PM     TSTM WND DMG     1 E CHERRY HILL         39.93N 75.01W
04/26/2019                   CAMDEN             NJ   PUBLIC           

            LARGE TREE UPROOTED AND FELL ACROSS RHODE 
            ISLAND AVENUE IN CHERRY HILL. TIME ESTIMATED 
            FROM RADAR. 

0544 PM     TSTM WND DMG     1 NE COLLINGSWOOD       39.93N 75.06W
04/26/2019                   CAMDEN             NJ   NEWSPAPER        

            DOWNED TREES CLOSED CUTHBERT BOULEVARD AND 
            PARK BOULEVARD NEAR CROWNE PLAZA. TIME 
            ESTIMATED FROM RADAR. 

0544 PM     TSTM WND DMG     1 NNW PHILADELPHIA      40.02N 75.14W
04/26/2019                   PHILADELPHIA       PA   FIRE DEPT/RESCUE 

            TREE UPROOTED AND BLOCKING THE ROADWAY NEAR 
            THE INTERSECTION OF TWINING ROAD AND DALE 
            ROAD. TIME ESTIMATED FROM RADAR. 

0542 PM     TSTM WND DMG     1 S ELKINS PARK         40.06N 75.13W
04/26/2019                   MONTGOMERY         PA   PUBLIC           

            DOWNED TREES AND POWER LINES NEAR MELROSE 
            PARK STATION. TIME ESTIMATED FROM RADAR. 

0540 PM     TSTM WND DMG     1 SW ELKINS PARK        40.06N 75.14W
04/26/2019                   PHILADELPHIA       PA   PUBLIC           

            DOWNED TREE DAMAGED A HOUSE IN WEST OAK 
            LANE. TIME ESTIMATED FROM RADAR. 

0537 PM     TSTM WND DMG     1 SSE LOGAN TWP.        39.79N 75.34W
04/26/2019                   GLOUCESTER         NJ   DEPT OF HIGHWAYS 

            TREE DOWN ON US 322 EASTBOUND WEST OF I-295 
            IN LOGAN TOWNSHIP. LANES ARE BLOCKED. TIME 
            ESTIMATED FROM RADAR. 

0535 PM     MARINE TSTM WIND FORTESCUE               39.24N 75.18W
04/26/2019  M41 MPH          ANZ430             NJ   MESONET          

            WINDS OF 36 KNOTS REPORTED AT FORTESCUE 
            NJWXNET SITE. 

0533 PM     TSTM WND DMG     MANAYUNK                40.02N 75.22W
04/26/2019                   PHILADELPHIA       PA   PUBLIC           

            DOWNED TREES AT AND NEAR BOONE PARK. TIME 
            ESTIMATED FROM RADAR. 

0532 PM     TSTM WND GST     PHILADELPHIA INTERNATIO 39.88N 75.23W
04/26/2019  M47 MPH          PHILADELPHIA       PA   ASOS             

             

0531 PM     TSTM WND DMG     1 SE ARDMORE            40.00N 75.28W
04/26/2019                   MONTGOMERY         PA   FIRE DEPT/RESCUE 

            DOWNED TREE AT MIDFIELD ROAD AND LAKESIDE 
            ROAD INTERSECTION, WITH ROADS BLOCKED. TIME 
            ESTIMATED FROM RADAR. 

0531 PM     TSTM WND DMG     NARBERTH                40.01N 75.26W
04/26/2019                   MONTGOMERY         PA   FIRE DEPT/RESCUE 

            DOWNED TREE NEAR THE INTERSECTION OF FORREST 
            AVENUE AND WINDSOR AVENUE. TIME ESTIMATED 
            FROM RADAR. 

0531 PM     TSTM WND DMG     BELMONT HILLS           40.02N 75.23W
04/26/2019                   MONTGOMERY         PA   BROADCAST MEDIA  

            SEVERAL TREES AND POWER LINES DOWN IN BALA 
            CYNWYD. TIME ESTIMATED FROM RADAR. 

0531 PM     TSTM WND GST     PHILADELPHIA INTERNATIO 39.88N 75.23W
04/26/2019  E62 MPH          PHILADELPHIA       PA   OTHER FEDERAL    

            CORRECTS PREVIOUS TSTM WND GST REPORT FROM 
            PHILADELPHIA INTERNATIONAL AIRPORT. PHL ITWS 
            MEASURED A WIND GUST TO 54 KNOTS. 

0530 PM     TSTM WND DMG     1 S BRYN MAWR           40.02N 75.32W
04/26/2019                   MONTGOMERY         PA   BROADCAST MEDIA  

            TRAIN STUCK DUE TO TREES AND WIRES DOWN ON 
            THE SEPTA TRACKS NEAR BRYN MAWR. TIME 
            ESTIMATED FROM RADAR. 

0530 PM     TSTM WND DMG     1 SSE NARBERTH          40.00N 75.26W
04/26/2019                   MONTGOMERY         PA   FIRE DEPT/RESCUE 

            DOWNED TREE BLOCKING THE ROADWAY NEAR THE 
            INTERSECTION OF BOWMAN AVENUE AND KENMORE 
            ROAD. TIME ESTIMATED FROM RADAR. 

0529 PM     TSTM WND DMG     PENN WYNNE              39.98N 75.28W
04/26/2019                   MONTGOMERY         PA   FIRE DEPT/RESCUE 

            DOWNED TREE AT INTERSECTION OF MANOA ROAD 
            AND TRENT ROAD. TIME ESTIMATED FROM RADAR. 

0528 PM     TSTM WND DMG     ALLOWAY                 39.56N 75.35W
04/26/2019                   SALEM              NJ   TRAINED SPOTTER  

            MULTIPLE TREES DOWN AND SHED DESTROYED. 

0518 PM     MARINE TSTM WIND 6 ESE WOODLAND BEACH    39.31N 75.38W
04/26/2019  M46 MPH          ANZ430             DE   MESONET          

            SHIP JOHN SHOAL BUOY MEASURED A GUST OF 40 
            KNOTS. 

0514 PM     TSTM WND DMG     1 NNW LIMA              39.93N 75.45W
04/26/2019                   DELAWARE           PA   911 CALL CENTER  

            DOWNED TREE ON WIRES NEAR THE INTERSECTION 
            OF MIDDLETOWN ROAD AND FORGE ROAD IN 
            MIDDLETOWN TWP. TIME ESTIMATED FROM RADAR. 

0505 PM     TSTM WND GST     4 SSW ELSINBORO TWP     39.48N 75.54W
04/26/2019  M60 MPH          SALEM              NJ   MESONET          

            MEASURED AT LOWER ALLOWAYS CREEK. 

0458 PM     TSTM WND DMG     SMYRNA                  39.30N 75.61W
04/26/2019                   KENT               DE   PUBLIC           

            LARGE TREES DOWN, SOME CAUSING PROPERTY 
            DAMAGE. TIME ESTIMATED FROM RADAR. 

0453 PM     TSTM WND DMG     ODESSA                  39.46N 75.66W
04/26/2019                   NEW CASTLE         DE   TRAINED SPOTTER  

            MULTIPLE LARGE TREES DAMAGED INCLUDING SOME 
            TREES SPLIT. 

0452 PM     TSTM WND GST     TOWNSEND                39.39N 75.69W
04/26/2019  M59 MPH          NEW CASTLE         DE   TRAINED SPOTTER  

             

0445 PM     TSTM WND GST     KENTON                  39.23N 75.66W
04/26/2019  M45 MPH          KENT               DE   MESONET          

             

0445 PM     TSTM WND DMG     2 WNW SAINT GEORGES     39.57N 75.69W
04/26/2019                   NEW CASTLE         DE   BROADCAST MEDIA  

            SEVERAL TREES WERE BLOWN DOWN IN A MOBILE 
            HOME PARK. TIME ESTIMATED FROM RADAR. 

0444 PM     TSTM WND DMG     AVONDALE                39.82N 75.78W
04/26/2019                   CHESTER            PA   BROADCAST MEDIA  

            A LARGE TREE DAMAGED A HOME AND TRAPPED TWO 
            INSIDE. NO INJURIES REPORTED. TIME ESTIMATED 
            FROM RADAR. 

0441 PM     TSTM WND DMG     1 S AVONDALE            39.81N 75.78W
04/26/2019                   CHESTER            PA   FIRE DEPT/RESCUE 

            TREE DOWN NEAR INTERSECTION OF ELLICOTT ROAD 
            AND COOPER ROAD. TIME ESTIMATED FROM RADAR. 

0436 PM     TSTM WND DMG     SUDLERSVILLE            39.19N 75.85W
04/26/2019                   QUEEN ANNES       MD   EMERGENCY MNGR   

            EMERGENCY SERVICES REPORTS TREES DOWN AROUND 
            THE AREA. TIME ESTIMATED FROM RADAR. 

0435 PM     TSTM WND GST     2 N GALENA              39.37N 75.88W
04/26/2019  M50 MPH          CECIL              MD   MESONET          

            MEASURED IN FREDERICKTOWN. 

0432 PM     TSTM WND DMG     1 N CRUMPTON            39.26N 75.93W
04/26/2019                   KENT               MD   PUBLIC           

            TREE DAMAGE AT A HOME NEAR ROUTE 290 AND 
            291. IRRIGATION SYSTEM ACROSS THE STREET 
            COLLAPSED. 

0432 PM     TSTM WND DMG     3 WNW SUDLERSVILLE      39.20N 75.90W
04/26/2019                   QUEEN ANNES       MD   DEPT OF HIGHWAYS 

            DOWNED TREES AND BLOWN DEBRIS CLOSED U.S. 
            HIGHWAY 301 NEAR DUDLEY CONNERS ROAD. TIME 
            ESTIMATED FROM RADAR. 

0428 PM     TSTM WND DMG     CARVILLE                39.05N 76.01W
04/26/2019                   QUEEN ANNES       MD   DEPT OF HIGHWAYS 

            DOWNED TREES AND BLOWN DEBRIS FORCED LANE 
            RESTRICTIONS ON U.S. HIGHWAY 301 AT STATE 
            HIGHWAY 305. TIME ESTIMATED FROM RADAR. 

0426 PM     TSTM WND DMG     3 NW HAMBLETON          38.73N 76.10W
04/26/2019                   TALBOT             MD   NEWSPAPER        

            TREE DOWN ON WIRES ON OLD COUNTRY CLUB ROAD. 
            TIME ESTIMATED FROM RADAR. 

0356 PM     MARINE TSTM WIND 1 E BARNEGAT LIGHT      39.76N 74.09W
04/26/2019  M42 MPH          ANZ451             NJ   MESONET          

            THE BARNEGAT ISLAND LIGHT WXFLOW SENSOR 
            REPORTED A WIND GUST OF 36.5 KNOTS. 


&&

$$

TCD

Radar Interrogation

Narberth Microburst (GR2Analyst)

Environment Environment
Figure 1: KDIX radar reflectivity factor (top left), base velocity (top right), correlation coefficient (bottom left), and differential reflectivity (bottom right) valid at 2121 UTC on 26 April 2019. Note the appearance of the line of storms bowing out between Media and Narberth, PA. This is a strong indication of strong winds aloft descending toward the surface. Figure 2: Same as Fig. 1, valid at 2126 UTC on 26 April 2019. Base velocities have increased considerably to the southwest of Narberth, to the point where velocity folding has occurred (in which the colors switch from green to red (or vice versa) whenever the velocities exceed a threshold value).
Environment Environment
Figure 3: Same as Fig. 1, valid at 2131 UTC on 26 April 2019. The strong surface winds have reached Narberth by this time. Figure 4: Same as Fig. 1, valid at 2135 UTC on 26 April 2019. The winds are beginning to diminish as the storm continues northeastward into Philadelphia County.

Cherry Hill Microburst (GR2Analyst)

Environment Environment
Figure 5: Same as Fig. 1, valid at 2144 UTC on 26 April 2019. Note the bowing segment near Haddonfield. This has a similar appearance to the Narberth case. Figure 6: Same as Fig. 1, valid at 2149 UTC on 26 April 2019. Base velocities are increasing just upstream of the bowing segment (near and just northeast of Haddonfield).
Environment Environment
Figure 7: Same as Fig. 1, valid at 2153 UTC on 26 April 2019. Base velocities continue to increase northeast of Haddonfield, coinciding with fairly widespread wind damage near Cherry Hill. Figure 8: Same as Fig. 1, valid at 2158 UTC on 26 April 2019. The base velocities begin to decrease as the storm enters Burlington County.