U.S. WIND, SCS, FLOOD, WINTER WEATHER

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1 U.S. WIND, SCS, FLOOD, WINTER WEATHER The threat continues for strong winds, heavy snow, heavy rain and severe thunderstorms according to the U.S. National Weather Service (NWS). The threat comes with an unusually strong frontal system crossing from the Southern Rockies through the Central Great Lakes. The wind threat continues to affect areas including the Southern and Central Plains, where wind gusts could reach mph according to NWS statements. Downed trees and powerlines with some damage to property and vehicles can be expected. For areas of the Central and Northern Plains, heavy snowfall amounts exceeding 8-12 inches, together with strong winds are expected to produce reduced visibilities and probable blizzard conditions, with significant transportation disruption. The heavy snow should move into South-Central Canada this evening. For portions of the Upper Mississippi Valley and Central Great Lakes, heavy rainfall will produce a considerable threat for flooding and flash flooding, due to rainwater combined with the existing snowpack, warming temperatures and frozen ground. The combined weight of the snowpack together with rainwater also amplifies the threat of roof collapse in certain areas. Heavy rainfall will also maintain the flood threat for the Central and Lower Mississippi Valley and adjacent watersheds. Meanwhile in the Lower and Central Mississippi Valley, an enhanced risk for severe thunderstorms has been flagged by the U.S. Storm Prediction Center (SPC). Damaging nontornadic wind gusts are the key threat expected by the SPC along with hail and some tornadoes. For tomorrow, an SPC slight risk will affect areas from the Northern Gulf to the Lower Great Lakes, primarily for the threat of nontornadic wind gusts and hail along with some tornadoes. Severe thunderstorms yesterday produced SPC reports of damaging nontornadic wind gusts along with hail and a few tornado reports from Eastern New Mexico across North Texas and portions of Oklahoma.

2 The storm, unofficially named "Ulmer" by the Weather Channel, comes with a potent upper-level system crossing the Rockies with robust upper-air support. This has developed an impressive surface low now moving through the Central Plains. Analysis of this feature by the U.S. Weather Prediction Center (WPC) estimates a surface pressure of 975 mb, after falling well over 24 mb in 24 hours (a clear case of "bomb cyclogenesis"). The resulting pressure gradient around this low is driving a significant wind threat. Meanwhile the upper-air mechanics together with abundant moisture will produce heavy precipitation. The system is also expected by the NWS to initiate severe thunderstorms to the south, in the presence of warm, moist and unstable air along with upper-air support. The U.S. National Weather Service (NWS) and the Meteorological Service of Canada (MSC) have issued watches, warnings and statements for areas under potential or imminent threat, and these will be updated as the situation evolves. Official watches and warnings, and statements from emergency management agencies supersede this update, and should be closely followed concerning matters of personal safety. Local watches and warnings can be found at weather.gov for U.S. locations, and at weather.gc.ca for locations in Canada. For further details affecting your area of responsibility, please contact me. Severe Thunderstorm Outlook - Today Orange - Enhanced Risk for Severe Thunderstorms Yellow - Slight Risk for Severe Thunderstorms Dark Green - Marginal Risk for Severe Thunderstorms Light Green - General Risk for Thunderstorms SOURCE: NOAA/SPC

3 National Forecast Chart - Today Severe Thunderstorm Outlook - Tomorrow Yellow - Slight Risk for Severe Thunderstorms Dark Green - Marginal Risk for Severe Thunderstorms Light Green - General Risk for Thunderstorms SOURCE: NOAA/SPC

4 National Forecast Chart - Tomorrow National Forecast Chart - Friday

5 Probability of Snowfall of 8 inches (20 cm) or More 48 Hours Ending 8AM EDT (12 UTC) Friday March 15 Forecast Precipitation Amounts (liquid or liquid equivalent) 48 Hours Ending 8AM EDT (12 UTC) Friday March 15

6 Significant River Flood Outlook - March Severe Thunderstorm Reports Yesterday SOURCE: NOAA/SPC

7 James Waller,PhD Research Meteorlogist (Desk) (Mobile) Guy Carpenter & Company LLC Guy Carpenter & Company, LLC provides this report for general information only. The information contained herein is based on sources we believe reliable, but we do not guarantee its accuracy, and it should be understood to be general insurance/reinsurance information only. Guy Carpenter & Company, LLC makes no representations or warranties, express or implied. The information is not intended to be taken as advice with respect to any individual situation and cannot be relied upon as such. Please consult your insurance/reinsurance advisors with respect to individual coverage issues. Readers are cautioned not to place undue reliance on any historical, current or forward-looking statements. Guy Carpenter & Company, LLC undertakes no obligation to update or revise publicly any historical, current or forward-looking statements, whether as a result of new information, research, future events or otherwise. This document or any portion of the information it contains may not be copied or reproduced in any form without the permission of Guy Carpenter & Company, LLC, except that clients of Guy Carpenter & Company, LLC need not obtain such permission when using this report for their internal purposes. The trademarks and service marks contained herein are the property of their respective owners. MARSH GUY CARPENTER MERCER OLIVER WYMAN Guy Carpenter 1166 Avenue of the Americas, New York, NY, USA