March 16, 2016: Strong Winds & Picturesque Showers

Overview

Wind gusts of 50 to nearly 60 mph were observed across northern Illinois and northwest Indiana.

The peak wind gust at Chicago O'Hare International Airport during the day was 50 mph and then in the evening was 53 mph with a shower.

The official peak wind gust at Rockford was 50 mph.

The strongest wind gust observed was 59 mph at Valparaiso, Indiana.

Gusty showers developed in the late afternoon and early evening. These isolated showers in a fairly dry atmosphere allowed them to be seen from a high distance. Their convective nature, or ability for warm air to rise quickly with cold air above it, led to some amazing cloud structure. With the lower sun angle near sundown, this set the stage for impressive photos that were provided to the NWS.

Peak Wind Gusts

Reports

In Lyons, IL, from Kevin Sheeley

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
434 AM CDT THU MAR 17 2016

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

1200 PM     NON-TSTM WND DMG WHEATON                 41.86N 88.11W
03/16/2016                   DUPAGE             IL   PUBLIC

            SMALL TREE BLOWN DOWN IN BACKYARD. TIME ESTIMATED. REPORT
            RELAYED VIA TWITTER.

1249 PM     NON-TSTM WND GST LIBERTYVILLE            42.28N 87.97W
03/16/2016  M55.00 MPH       LAKE               IL   EMERGENCY MNGR

0200 PM     NON-TSTM WND DMG LYONS                   41.81N 87.82W
03/16/2016                   COOK               IL   PUBLIC

            TREE UPROOTED AND FELL ON HOUSE. REPORT RELAYED VIA
            FACEBOOK. TIME ESTIMATED.

0255 PM     NON-TSTM WND GST VALPARAISO              41.48N 87.05W
03/16/2016  M59.00 MPH       PORTER             IN   ASOS

            51 KT GUST.

0310 PM     NON-TSTM WND DMG BENSENVILLE             41.96N 87.94W
03/16/2016                   DUPAGE             IL   EMERGENCY MNGR

            AN 18-20 INCH DIAMETER TREE SNAPPED AT BASE AND FELL ONTO
            POWER LINES. TIME IS ESTIMATED FROM THE POWER OUTAGE
            REPORTS FROM EMERGENCY MANAGEMENT.

0330 PM     NON-TSTM WND DMG CHERRY VALLEY           42.24N 88.96W
03/16/2016                   WINNEBAGO          IL   BROADCAST MEDIA

            THREE FOOT DIAMETER TREE BLOWN DOWN.

0400 PM     NON-TSTM WND DMG CHICAGO                 41.88N 87.63W
03/16/2016                   COOK               IL   PUBLIC

            STREET LAMP DOWN. EXACT TIME ESTIMATED/UNKNOWN. RELAYED
            VIA TWITTER.

0400 PM     NON-TSTM WND DMG BENSENVILLE             41.96N 87.94W
03/16/2016                   DUPAGE             IL   EMERGENCY MNGR

            EMERGENCY MANAGEMENT RELAYED THAT A TREE FELL ONTO A HOME
            IN BENSENVILLE IL.

0452 PM     NON-TSTM WND GST 5 SSE BEACH PARK        42.36N 87.81W
03/16/2016  M58.00 MPH       LMZ740             IL   C-MAN STATION


&&

$$

MTF

Meteorology

Mean sea-level pressure loop through the day Wednesday, March 16th

Mid-Afternoon through evening water vapor loop on March 16th showing an upper level disturbance and resulting shower and isolated storm development.


Observed Radiosonde Sounding from 7pm weather balloon launch at NWS Quad Cities in Davenport, IA on March 16th.	Observed Radiosonde Sounding from 7pm weather balloon launch at NWS Lincoln, IL on March 16th.

The above observed evening soundings demonstrate the dry, deeply mixed atmosphere conducive for the strong winds during the day and also the convective showers that developed late in the day. Steep lapse rates (falling temperatures with height) at a very deep layer of the atmosphere to over 10,000 feet above ground level exhibited deep atmospheric mixing. This mixing allowed strong unidirectional westerly winds throughout the column to be easily transported down as frequent wind gusts, in addition to the already strong surface winds caused by the tight pressure gradient over the region. In addition, the steep lapse rates created minor atmospheric instability, known as CAPE, and also the potential for rapid rising motions once an upper level disturbance initiated the process of lifting the airmass. Despite the overall dry airmass in place, there was just enough moisture, combined with the minor instability levels and steep lapse rates conducive for strong updrafts to create the convective showers and a few thunderstorms. These showers occurring in a dry atmosphere led to impressive cloud structure seen below.

Cloud Photos

Northeast of LaSalle, IL from Al Steinz


Aurora from Kyle Brown	Chicago from Barry Butler


Carol Stream from Jamie Hansen	Des Plaines from Sawi Paulie


Dundee from Jen Reid	Elgin from JoAnna Marie


Chicago Midway International Airport from Derrick Helton	Between Byron and Rockford from Karissa Gelafio


Crystal Lake from Haley Denley	Hometown from Nick Lamacki

Outside of NWS Chicago office in Romeoville, IL. Courtesy of Ricky Castro.

Outside of NWS Chicago office in Romeoville, IL from Ricky Castro

Other Info

Snow Across the Great Lakes, Central Appalachians, and Northeast; Unsettled Weather in the West

March 16, 2016: Strong Winds & Picturesque Showers